Call centers often demand employees hit a certain number of calls per day, even when that isn't the actual goal of the company. In this case, OP was working at a call center for a collection agency, whose main target was to collect debts, generating revenue for the company. OP was doing really well, but sometimes they missed the daily target, and managers would dwell on their call count, instead of taking a look at the numbers OP was generating for the company.
OP found out that the company was grossly skimming his and other employees' bonuses that OP's department's client had been providing them as a reward for successfully collecting on these debts. The under-appreciation OP was receiving from his company in literally every form made him decide that enough was enough… OP began quietly quitting, and soon enough, the company was losing a lot of money as a result.
Management noticed pretty quickly, as OP's revenue dropped by a whopping 80%. But hey, at least he was hitting his daily call targets, right? Management approached OP with quite a few questions, but OP's malicious compliance was well thought out, and management couldn't quite pinpoint what was going on.
Scroll down to read what happened next. For more, here is an employee who got their boss fired during a disciplinary hearing that was actually designated for the employee himself.