First recorded complaint letter!

https://en.wikipedia.org/wiki/Complaint_tablet_to_Ea-nasir

In response, Nanni created the cuneiform letter for delivery to Ea-nasir. Inscribed on it is a complaint to Ea-nasir about a copper delivery of the incorrect grade, and issues with another delivery;^[5] Nanni also complained that his servant (who handled the transaction) had been treated rudely. He stated that, at the time of writing, he had not accepted the copper, but had paid the money for it.