How to Reply to an Invoice Query From a Client
How to reply to an invoice query from a client: email templates for questions on hours, prices, tax, missing PO numbers and duplicates, with a worked example.
A client emails: "Can you explain line 3 on this invoice?" How you reply to an invoice query decides whether you are paid on time or the invoice sits on hold for weeks. The best reply acknowledges the question quickly, answers it with evidence, states clearly what the client owes and what happens next, and corrects the invoice immediately if the client turns out to be right.
This guide gives you a reply framework, templates for the most common invoice queries and a worked example showing how to split a queried invoice so the undisputed amount can still be paid.
Common types of invoice query
| Query | What usually answers it |
|---|---|
| "Why is the price higher than the quote?" | Approved change order, variation email, or price clause |
| "We expected fewer hours." | Timesheet with dates and tasks; see our timesheet template |
| "What is this charge?" | A plain-language description and the contract reference |
| "The invoice has no PO number." | Reissue a corrected copy with the PO |
| "Why is tax charged?" or "Wrong tax rate" | Your tax registration and the rate that applies |
| "Have we already paid this?" | A statement of account showing payments and open items |
| "Can we have a copy?" | A copy of the original, clearly labelled; see duplicate invoice copy |
A four-step framework for replying
- Acknowledge the same day. Thank them, restate the question and give a date for the full answer.
- Check the facts against the contract, quote, timesheets and delivery records before replying in substance.
- Answer with evidence, not opinion. Attach the document and point to the exact line.
- Close the loop: state the amount now due, the due date, and whether anything is being corrected.
Templates: how to reply to an invoice query
1. Holding reply
Hi Laura,
Thanks for your question about line 3 on invoice INV-3051. I am checking the timesheet and will reply in full by Thursday 14 November. If the rest of the invoice is fine, it would help if it could continue through approval in the meantime.
Ravi
2. Hours questioned, and the invoice is correct
Hi Laura,
Thanks for your patience. Line 3 covers 16 hours of data migration between 6 and 10 October. The attached timesheet breaks this down by day and task, and the extra 6 hours above the estimate were approved by Mark in his email of 7 October (also attached). The invoice total of USD 6,500.00 is therefore correct and due on 2 December. Happy to walk through it on a call if useful.
Ravi
3. Price higher than the quote
Hi Rachel,
The invoice is GBP 480.00 above quote Q-311 because of the additional drainage work on 28 October. You approved this as variation V-02 by email that day; I have attached a copy. All other lines match the quote exactly.
Daniel
4. The client is right
Hi Sam,
You are right, thank you for catching it. Line 2 should have been 12 hours, not 20. I have attached credit note CN-014 for USD 760.00, which brings the balance on INV-1042 to USD 1,140.00. The due date is unchanged.
Ana
For more wording when the error is yours, see our apology email for a wrong invoice.
5. Missing PO number
Hi Accounts team,
Thanks for letting me know. Attached is a corrected copy of invoice CF-0921, with the same number, date and amount, now showing PO-2251. Please replace the earlier version with this one.
Coastal Facilities
6. Tax question
Hi Omar,
We charge VAT because we are VAT registered (TRN shown at the top of the invoice), and our services are standard rated at 5%. The VAT on INV-0981 is 3,500.00 x 5% = 175.00, giving a total of AED 3,675.00. Let me know if your team needs our tax registration certificate.
Noor
7. "Have we already paid this?"
Hi Kate,
I have attached your statement of account. Payments of USD 320.00 (INV-1061) and USD 480.00 (INV-1062) were received on 3 and 10 November, thank you. INV-1063 for USD 960.00 is the only open item, due 14 November.
Ben
8. Partial agreement: pay the undisputed amount
Hi James,
I have looked into line 3 (on-site support) on invoice AG-5520. Our records show 24 hours, while yours show 20, and I am confirming with the engineer. So the rest of the invoice is not held up, I have issued credit note CN-033 for the 4 queried hours (4 x 150.00 = 600.00). The balance of USD 18,000.00 can be approved now, and I will rebill the 4 hours separately if our records are confirmed.
Atlas Group accounts
Worked example: splitting a queried invoice
Template 8 in numbers. The client queries 4 of the 24 hours billed for on-site support:
| Line | Calculation | Amount (USD) |
|---|---|---|
| Hardware supply | Agreed | 12,000.00 |
| Installation | Agreed | 3,000.00 |
| On-site support | 24 h x 150.00 | 3,600.00 |
| Invoice AG-5520 total | 12,000 + 3,000 + 3,600 | 18,600.00 |
| Credit note CN-033 (queried hours) | 4 h x 150.00 | -600.00 |
| Undisputed amount to approve now | 18,600.00 - 600.00 | 18,000.00 |
Waiting for the 600.00 question to be resolved would have held up 18,000.00. Splitting it keeps cash flowing. If the hours are confirmed, a new invoice for 600.00 follows; if not, the credit stands.
Queries about missing invoice details
Some queries are not about the amount at all but about whether the invoice contains what the client's AP team or auditors need. In the UK, GOV.UK lists what an invoice must include: a unique invoice number, your business name, address and contact details, the customer's name and address, a clear description of what you are charging for, the supply date, the invoice date, the amount for each item, any VAT and the total owed. VAT-registered businesses selling to other VAT-registered businesses need a full VAT invoice with more detail (GOV.UK: invoices, what they must include). Other countries have their own lists.
If a query says a required detail is missing, the fix is a corrected copy or a credit note and replacement, not an argument. This is general information, not tax advice.
Phrases that keep the conversation calm
- "Thanks for checking this. I will look into it today."
- "Here is the breakdown behind line 3, with the timesheet attached."
- "You are right about the rate; I have corrected it below."
- "So the rest of the invoice is not held up, could the undisputed amount be approved now?"
- "Would a quick call help? I am free Thursday morning."
- "To confirm what we agreed: credit of 600.00, balance due 18,000.00 by 10 December."
Notice that none of them ask the client to justify the question. Treating queries as normal makes clients more likely to raise issues early, which is when they are cheapest to fix.
When a query turns into a dispute
If the client rejects your evidence, stops replying, or says work was not delivered, treat it as an invoice dispute. Move discussion to a call, propose specific options (partial credit, extra work to fix the issue, or the contract's dispute process) and confirm any agreement in writing. Only start late-payment steps on amounts that are not in genuine dispute.
Keep a record of every query
Log each query with the date raised, the invoice and line involved, your answer and the outcome. Over a few months the log shows patterns: perhaps one client always questions travel time, or a particular service description confuses people. Fixing the cause, by adding detail to that line item or agreeing travel charges in the contract, is the best way to reduce future queries. The log also helps if a query later becomes a dispute, because you can show when the client first raised the issue and how quickly you answered.
Preventing invoice queries
- Describe line items clearly: "Data migration, 6 to 10 October, 16 h" rather than "Services".
- Put the PO number and the client's legal name on every invoice.
- Attach timesheets or delivery notes with the invoice for hourly or variable work.
- Get variations approved in writing before you do the work.
- Ask AP for confirmation of receipt so problems surface early; many teams send an invoice received acknowledgement.
Mistakes to avoid
- Getting defensive or treating a question as an accusation.
- Answering from memory instead of checking the records.
- Letting a small query hold the whole invoice.
- Changing figures on a recorded invoice instead of using a credit note.
- Leaving the conversation without a clear amount due and date.
Clear invoices get fewer questions. Our invoice generator lets you add detailed line items, PO numbers and notes, then download a PDF for free without creating an account.
Frequently asked questions
How quickly should I reply to an invoice query?
Acknowledge it the same working day if you can, even if the full answer takes longer. A two-line holding reply such as "Thanks, I am checking the timesheet and will come back to you by Thursday" keeps the invoice moving. Slow replies often turn a simple question into a late payment, because the client's AP team will hold the invoice until the query is closed.
What is the difference between an invoice query and an invoice dispute?
A query is a question: the client wants an explanation, a document or a small correction before paying. A dispute is a disagreement: the client says the charge is wrong or the work was not delivered as agreed and refuses to pay all or part of it. Most disputes start as queries, so a fast, factual answer to the query is the best way to prevent one.
Should I ask the client to pay the undisputed part of the invoice?
Yes, it is reasonable to ask. If the query concerns one line, for example 4 hours of a 40-hour invoice, ask the client to pay the rest while you resolve the question. Some businesses issue a credit note for the queried line and rebill it later once agreed, which lets the AP system approve the remainder without waiting.
What documents should I send with my reply?
Send whatever proves the charge: the signed quote or contract clause for price questions, timesheets for hours, delivery notes or proof of delivery for goods, approved change orders for extras, and a statement of account for balance questions. Attach only what answers the question, and refer to page or line numbers so the client can check quickly.
How do I reply if the client is right and the invoice is wrong?
Thank them for spotting it, confirm the error in one sentence and send the correction straight away, usually a credit note and, if needed, a replacement invoice. Do not argue over small amounts or delay the fix to check other lines unless there is reason to. A quick, gracious correction protects the relationship and gets the rest of the invoice paid.
Invoice Creator Editorial Team
Guides on invoicing, cash flow and small-business finance from Invoice Creator, operated by Next Software Development Company. Content is reviewed for accuracy against the fields our own invoice generator produces.
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