First, each state has a board that handles complaints about doctors. They can usually be found under consumer protection listings in your state. Most of the time, a complaint can be filed online.
Second, to privately sue a physician for something like this, you would want to find an attorney who specializes in consumer fraud, because even as a patient, you are a consumer who is buying his services. Have a feeling the doctor may be defrauding more than just you and your insurance company, most likely Medicare and Medicaid, too. Call your County or State Bar Association. They may be able to refer you. If this were Medicare or Medicaid, I would suggest that you find an attorney who specializes in what is called "qui tam". When a private citizen helps to prosecute Medicare or Medicaid fraud by a doctor, the law of "qui tam" allows that citizen to receive part of the recovery. Perhaps, if you find a qui tam attorney in your area, he or she could refer you to an equally knwledgable attorney who handles commercial insurance fraud.
Thank you for being so brave, because most people who experience this keep their mouths shut. Every once in awhile, I come across someone who says, "No way! This is wrong and I am not going to let you do this anymore, to me or anyone else!"
Upbilling or upcoding is fraud. It is illegal in every state in this country and on the federal level. As for charging for visits that you never had, that is the epitomy of theft.