People can be so nasty, can't they?
I used to work in a bookshop, and a handful of the customers reduced me to tears.
It really is their problem. It really, really is. either something quite out-of-control has happened in their lives that;s made them behave in such a vile way to someone defenceless and undeserving of their nastiness or they have issues with their personality. The former situation is, of course, sad; the latter, somewhat joyful, because if you drag a personality like that around, you're effectively condemning yourself to a life with all the joy bled from it. An apt punishment for crapness. I think Dante would visualise them as wading through a river of shit, carrying a bag of vomit, for eternity.
Apparently, if I was still working there, I could de-magnetise their cards, or something, as a small act of spiteful revenge. I was working there prior to credit cards, and I guess you don't have that option.
Which is probably as well, really. Because it would just make you as mean as them.
Well, on the plus side, you're not going home to them.