The customers,
Upper management will try to do anything to deduct your pay including tech issues or being a single minute back from break etc. it's a high pressure job so it kind of makes sense but the problem is the pay is minimum wage so it doesn't remotely match the high pressure. In short they'd pay you even less if it was legal. In training you are taught the importance of empathy when handling calls, Unfortunately this empathy training didn't extend to HR. Phoning in sick if you are unwell is not a pleasant experience