Last week, I notified a customer about that their webbserver spewed out several thousands of spam emails every hour, and they have to fix it ASAP.
(I also inform them for the 50th times for the last 2 years that they really need to update their websites so we can update from Debian 5).

The owner of the company forward this to their developers.

Today, I got the answer from them denying everything and blaming our "negligence" and they also dared to question all our technical expertise. shots fired

Spend some hours, finding shit on their websites, dug out logs, read documentation and old conversation and compiled that into a huge email that was designed to put them 10 meters under ground.

mfw I pressed send