M & T Bank

Let me start by saying this review is for this branch only. I like M & T bank, and have had them since I moved here years ago.
Every once in a while I make the mistake of going inside this branch. Every time I kick myself for forgetting about the brain-​dead zombies that work here.
Latest attempt at customer service (monetary amounts have been changed):
Me: (presenting 2 checks totalling $ 500 with deposit slip)
Teller (in broken English): «You want $ 20 back?»
Me: «Yes.»
Teller: «I can’t do that.»
Me: «Why not?»
Teller: «Because you are cashing these checks, and you only have $ 300 in your account.»
Me: «Right. I have $ 300 in my account, so take the $ 20 out of there.»
Teller: «I can’t do that.»
Second teller (in just-​as-​broken-​English): «You can’t do that.»
Me: «How bout you just deposit those checks, and I’ll get the $ 20 out of the ATM?»
Tellers (in unison): «Ok.»
???
This branch used to be a few blocks away, and everything was fine. With the change in location came a change in staff. Where did the good workers go? If I find them, I will use that branch for my in-​person bank needs. Otherwise, its to the ATM I go.