I used to work in a kitchen at a bar/restaurant. I was fired over the phone for missing a shift. Now the owners have told me I am not allowed in the establishment. Is that legal without a reason??
Generally, yes it is legal. If you are an at-will employee, you can be fired for any reason at all as long as that reason is not because of discrimination. Here it looks like you were fired for missing a shift, which is legal. If you feel you were the victim of discrimination, then you should see an attorney.
It may have been legal to fire you for missing a shiftbut not to bar you from entering the restaurant as a customer. Good Luck!