How do I revoke a signature from a document?

NOT illegal. In fact, very standard.

The reason is that YOU ARE THE person who accepted the medical treatment, and the Dr. provided. YOU have a contract with your insurance. The Dr. has no contract with the insurance, and is free to set his fees as he chooses. He isn't obligated to conform to what your insurance will or won't pay.

The document was to inform you of this.. and make sure you understand. If the Dr. DID have an agreement with your insurance, that's different. Most Dr.'s do not.

Ask the doctor's office (you should have done this first) why they are charging you $1000 above what the insurance paid. They may have a legit reason.

Next, YOU legally agreed to pay any fees above what your insurance pays. You cannot sign a contract then renege when you don't like the consequences. That would be like me hiring you for a job but come pay day saying I don't like that I have to pay you the salary we agreed on so I won't. You agreed to the terms, the doctor did his job, now you have to pay for the services you requested of him. Just like with any other store or service.

You should have talked to the office BEFORE it went this far. If it has gone to collection it is not on your credit report for all to see.

You can send (certified) your response of why you do not wish to pay... i.e. DISPUTE the bill. Be sure to word it well.... then wait for their response. Everyone signs that agreement, but you cannot revoke something after you receive the service. You also need to go to your credit bureau and make note on your credit report if they have given you a bad report.

You take everything to a good local contract lawyer and see if he thinks he can do anything.

You might also call your insurance company and see if they have a legal issue with his provider agreement and this arrangement.

You can't revoke it now.