FICTIONAL DOCUMENT FOR PRACTICE - no reference to real people, companies or records

From: purchasing office, Bassett Hardware (customer)
Subject: WRONG invoice AGAIN!!!

Good morning,
this is the second time in a month that you have sent us an invoice with the wrong price. The price list agreed in January for M6 stainless steel screws was £0.18 per piece and you keep invoicing 0.21. Invoice 412 of 3 October is for 5,000 pieces, which is a difference of £150. I already wrote on 12 September and nobody replied.
If I do not receive a credit note by Friday we will stop all payments in progress and look at other suppliers.
Regards
Purchasing manager

INTERNAL NOTES (use only these):
- The 2026 price list signed in January says 0.18 for M6 stainless screws up to 10,000 pieces a year.
- The customer went over 10,000 pieces in September: above that threshold the price list says 0.21. So invoice 412 is correct.
- The email of 12 September was received but never answered: our mistake.
- We can offer a 3% discount on the next order as an apology for the late reply, not a credit note.