Customer Complaint — How to Settle VAT and Issue a Correction Invoice in 2026

Situations Requiring a Correction Invoice

• Quality complaint — defective goods, customer returns them
• Quantity discrepancy — delivery smaller than stated on the invoice
• Price error — e.g., incorrect VAT rate entered
• Partial return — customer returns part of the order
• Post-sale discount — e.g., for early payment
• Change in VAT rate — very rare, but it happens

Correction Issuance Procedure (Seller)

1. Receiving the complaint — in writing (email, letter)
2. Accepting the complaint — decision on refund / discount
3. Issuing a correction invoice — via KSeF (National e-Invoicing System, mandatory from April 2026)
4. The invoice must contain: correction number, date, reference to the original invoice, amount of the change
5. Sending to the buyer — through KSeF or directly
6. JPK_V7M (Standard Audit File for Tax) correction — in the current reporting period (not retroactively!)

Downward Correction vs Upward Correction

Downward correction (decrease) — refund, discount, quantity shortfall. Requires confirmation from the buyer (an email with acceptance is sufficient):

• Without confirmation — the buyer does not recognize the correction, and the seller cannot apply it either
• With confirmation — both parties correct in the current tax return

Upward correction (increase) — e.g., additional service, customer received more. No confirmation from the buyer required — the seller corrects immediately.

Procedure for the Buyer

The buyer receives the correction invoice and:

1. Verifies it against the original invoice and complaint
2. Accepts it (by email or through KSeF) — required for downward corrections
3. Corrects their JPK_V7M return — in the current period
4. If VAT from the original invoice was already deducted — the deducted VAT decreases by the correction amount
5. If it is an upward correction — the buyer increases the deduction

Most Common Mistakes

• No acceptance from the buyer for a downward correction = the seller cannot reduce VAT
• Retroactive correction — in the return for the previous month. Incorrect — corrections are made in the current period
• No reference to the original invoice — a formal error, the tax office may challenge it
• Treating a correction as a cancellation — these are NOT the same. Cancellation = zero correction + new invoice. Partial return = downward correction for a specific amount

Frequently Asked Questions