Dear Felix
Since we value your business greatly, I have been inspecting our invoices to ensure that we have made no errors.
You can understand, then, my embarrassment when I uncovered an error on our invoice #[ INVOICE NUMBER]. [STATE ERROR, ex. Although we shipped to you five Magna flux compressors, per your order, we incorrectly billed you for four compressors.] Please check your records and notify me if I am mistaken.
I will nullify that invoice ( #[INVOICE NUMBER, ex. #A423F] ) and issue you a new one as follows:
[LIST NEW INVOICE DETAILS, ex.
5 Magna flux compressors @ $4,000 $20,000
Tax @ 5% 1,000
Total $21,000]
Let me assure you that I will personally inspect our invoices to you in the future to ensure that there will be no further errors. Feel free to contact me at XXX-XX-XX if there are any issues you wish me to address.
Regards
Lydia