If they never did the procedure, they are committing fraud; and if they are charging you more than they agreed to charge (though this can be difficult to prove if you don't have anything in writing, like a quote or estimate), they are in breach of contract, too. Of these two things, trying to charge for work they never did is more serious and provides more leverage; assuming you could convince a court of your claims, you should not have to pay these amounts.You could tell the doctor's office that if they keep trying to bill you an excessive amount and especially for a procedure they never did, you will file a complaint with your state's medical licensing board; report them for fraud to the state attorney general; and if they pursue this matter and try to collect from you, will sue or countersue them for fraud, consummer fraud, and abuse of process.