I don't know what kind of call-centre you are working at.
But, no matter if it is inbound or outbound, selling things or customer service, don't let the mood of the caller get to you.
Saw quite some people getting really upset, because of the way angry customers treated them.
But, in the end, they don't know you, and they are not calling you personally.
Angry customers call because they do have a real problem, that needs fixing, or, they are in a foul mood, and found something to bitch about to get it out of their system. Their neighbour, dog or spouse probably was not around to yell at, and, at least you are getting paid for being scolded. (Be it, very likely, not a brilliant salary)
In the first case, trying to fix it, or, logging the problem right, and reading out to them how you logged the problem will make that they feel taken serious.
The other case, letting them rage a bit can help. Though, sometimes you wonder. But it is not about you, and, realising that can make it easier.