I don't understand people...

I work in a small bar. We don't get A LOT of business. We have a small smoking room and 5 VLT machines. We do not have an ATM, nor are we allowed to give cash back. For some reason, people feel the need to get angry at me for this. "HOW can you NOT have an ATM?! You can ALTEAST give me cash back?!"
Last time I told someone "No, I'm sorry management says we're not allowed to give cash back" and they called in later (they forgot to pay their tab!!) and said I was rude?! How is that rude? How is it my fault for any of these things. Today this guy was like "WHAT...you're telling me there is not ATM? You have these VLT's and no ATM? What about upstairs? How about cash back? Ok then, so upstairs they can give me cash back. No? WHY NOT!"

Seriously, why do people take this out on me. I have brought it up to the manager, and she said no way will we get an ATM. I don't know why, but it's not really my business. there is a gas station like 2 mins away, if that, and they're too lazy to go there. They're so absorbed into gambling. It's sickning.

This other guy heard this guy going on about the ATM and was like "he's right you know". This guy has been in EVERYDAY for like 2 weeks now...he knows about the rules. He went on about how much business we're losing etc etc. -__-

So, can someone tell me WHY they do this to ME? Why not the manager or someone who has any sort of authority...I just work there, that's it. I pass their concerns on, but there is nothing I can do. *siiiggh* needed to vent that...