About 6 months ago I was travelling out of state when I got injured. It was not serious but I wanted to get checked out. I called my health insurance carrier and asked where I could be seen, preferably at a walk-in clinic. I was given the option of going to an Emergency Room, or an Urgent Care Clinic. I was advised my ER deductible is $100 and my Urgent Care deductible is $50. I said I would rather go to Urgent Care but was told the closest one to where I was staying was 70 miles away. Nonetheless, I went to this clinic to avoid having to go to an ER. At the time of my visit, I went into the Urgent Care clinic which was attached to the hospital. I paid my $50 co-pay. Several weeks later after returning home, I received a bill for $50, which stated it was for my co-pay. I wrote a letter back explaining I had already paid the co-pay and provided a copy of the check. A few weeks after that I got another bill, stating my co-pay was $100 and I still owed $50. My response was to send them a copy of my insurance card which shows the Urgent Care co-pay is $50. For the past 6 months we have been going back and forth. They still insist that I owe them another $50, and now they have turned me over to a collection agency. I have sent letters to my insurance company as well as the hospital itself and neither one has responded. Do I just give in and pay the $50 that I don't owe to avoid a mark on my credit, or should I keep fighting it? What is the best way to fight this?

Thanks!

Oops, I meant co-pay, not deductible.