What to do when someone twist words and rules around?

At my work there's this new rule about not eating out until payday Friday, but then half the supervisors seem to be twisting the words in that rule around. Saying that we can't even buy a SNACK or ANYTHING until a Friday. When I'm with the boss (also boss of supervisors) she LETs us buy a snack at lunch.What to do when someone twist words and rules around?
Force them to look at the rules, and alert your boss.What to do when someone twist words and rules around?
If they pay you for your lunchtime, I guess they can say if you can leave work to buy something or not but if your lunch is say, an unpaid half hour, I don't think they can tell you how to spend your time. You should be able to bring lunch or purchase it outside where you work if its all done within your allotted lunchtime. I don't get it, its your money, nobody should "let" you or "not let" you use it.

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