If a doctor is in network and your insurance pays him under contract, refer to your insurance companies EOB for the visit. It outlines the contractual amounts the doctor agreed to accept, the portion they are paying under your contract and the portion you are responsible for. Some providers attempt to "balance bill" "accidentally". In fact I just received a $3k "accident". Call them and remind them of what the EOB outlines, they should adjust it. If they do not call your insurance company and ask them to intervene.