Internal Medicine Physians Billing me a second time for paid bills Farmington Hills Michigan

Today, I received from the office (Billing) of my Primary Care Phyician (App. 8 doctors work there at present. A female clerk mentioned about changing an appointment in August. I did not have an appointment in August (I have my annual invNovember (Issue No. 1). She also stated that I owe  $25 copay from November of last years. I always pay my copay(s) and get a bill for any additional testing, etc. from the office and always pay the bill. I had been notified of this alleged bill when I was at the office for a followup to a left hip replacement on August 11. The entry clerk checked into it with her supervisor ans it was cleared. I only paid the $25 copay for that visit. The fact that the reportaed appointed was incorrect and clearance by a supervisor seems to indicate errors on the part of entry clerks. I was told that the alleged bill will be sent toa collection agency. I warn all patients to save all receipts. I only save them until, they clear my bank as they are not tax deductible for SSR.