June 3, 2020
Attn: [Recipient's Name]
[City], [State] [Zip Code]
Subject: Billing Error
I want to apologize for a billing error that we have discovered.
We investigated and found that a mistake was made on Invoice # from [Date]. On line #9, the quantity of 92 cases listed is incorrect. The number was transposed and should have been 29. We have checked our inventory and verified that 29, instead of 92, were delivered to you on [Date]. This means 63 cases were overcharged on Invoice #.
To correct this mistake I have cancelled Invoice # and created a new Invoice #. You will find the new invoice attached to this letter.
Thank you for your help with correcting this mistake. Please accept our apology for the error we made.
Attached: Invoice #