Sonic Drive Inn / bad management!

I am an current employee at sonic drive in and i am having trouble with some one using my employee number to make employee tickets and they have racked my bill up to $160.00 and i have made a complaint about it but unfortunately i have no proof that it was not me the thing is though you have to sign the receipts. I have not had to sign a single damn receipt since i have worked there. I can not eat fast food due to two severe ulcers. They are so bad that if i eat just hint of oil or spicy foods they start to bleed and i have already brought in a doctors note pertaining to my medical problem but they still insist i sat there and ate a hundred and sixty dollars worth the food (that could kill me) in two weeks. Sonic has a very bad system i mean all the managers have our information and there should only be certain really i am portal people with that kind of very important information. They need a higher and more secure system.