Arcadia Urgent Care

I was a patient at Arcadia Urgent Care in late 2011. I never received a bill or any communication regarding an outstanding balance. In February of 2014, I received a call from a collection agency regarding a late payment of $236 - over two years after the visit to Arcadia Urgent Care. After doing some research, I learned that my insurance agency had never received a claim for that appointment. I was surprised to learn that the Arcadia Urgent Care had billed my previous insurance company (who denied the claim since I was not an enrolled member) instead of the company whose card I had provided upon check-in. Until 2014, I was not contacted by phone or mail regarding any outstanding balance. It is obviously too late to submit the claim to my insurance provided (which would have cost me my $60 co-pay instead of $236). I was told by the collection agency that I need to pay immediately otherwise it will impact my credit score. The collection agency also informed me that someone new purchased Arcadia Urgent Care and is going after all outstanding debts. Apparently I'm just one of many people on their list who are on the hook for debts that didn't know existed.
Needless to say, I am very disappointed with how this progressed. It is unacceptable to send a bill to a collection agency two years after a service - and especially after not reaching out to the patient at all. Clearly my phone number still works as the collection agency was able to get me on the first try.