Sullivans Motorcycle Accessories

I received a bill after I already paid the amount due at the office
I went to East Tennessee state university college of nursing for x-raysI was told it was so I paid it in fullThen I received a bill for I called the companyShe said it was a mistake and not too worry about it that she would fix itI got another bill so I called again, the lady told me this happens allot and she would dispute itBut never called me backThen I received another bill saying past dueNow I can't get ahold of anyone when I call