When I was off the clock I went in to work to see if I could ask some one that I had been trying to call to work for me and my boss told me that I was not to call or bug them at work for some one to cover my shift. But there are some people that do that not just me. So I told my boss that that is bs that every one else can do that but me

Yes. The supervisor gave you a reasonable instruction that you refused to follow, and you were rude in the manner in which you replied. The supervisor has a responsibility to make sure the work is getting done--you were interrupting the work flow. You are responsible to follow the supervisor's reasonable requests whenever you are in the workplace, whether you're on the clock or not.

If you felt that the rules were not being applied fairly, then you should have gone to HR and not mouthed off to your supervisor, especially if this was in front of other employees.