It sounds like you are insured under an HMO plan. These are the types of health insurance policies that require you to choose a primary care physician at the time of your enrollment. Your insurance ID card should clearly show the name of your doctor, along with their address and phone number. The clinic where you received treatment should have clearly known that you're insurance, if it was an HMO plan, required you to use the medical facilities of your primary care physician. The contract you have with your insurance company will also state what your responsibilities are in obtaining health care under your specific health plan. HMO plans, unless being treated for a life-threatening emergency, require you to go through your chosen primary care physician, or use the urgent care or after-hours facility operated by that doctor's medical group. Your insurance company has every right to deny your claim, since you did not follow the procedures that are eplained in your policy details. It would seem that your complaint should be with the medical clinic that accepted your insurance ID card without eplaining to you the limitations of your insurance type. Did they make you sign anything that said you would be liable for the medical bills if your insurance company did not pay them?