I have to agree with what others said. If she's paying your bills, then she can make the rules.
However, I do think they are somewhat strict for a 21 year old.

If I may ask, why don't you pay your insurance and phone bill? You indicate that you are working, so what are you doing with your money, that you can't pay that? Do you give your mother anything in the way of room and board - do you help with groceries?

I'm not being nosy - just trying to get a better picture and maybe some suggestions for you.