[tagtastic]

Okay.. the point where you asked for a refund and she refused is the time YOU should have threatened to call the cops (and followed through).

While you probably looked like/are a douche, you did nothing wrong in this situation, and even if you did they cannot refuse to serve and not refund your money.

Take this up with the store manager (assuming it's not her), or further up the McD's corporate chain. There's a very good chance she will be fired if you talk to the right person.