My wife and I had something similar happen. She spent $600 at the eye doctor but I had our HSA cedit card on me that day. She called me with them and I paid over the phone. Well fast forward 30 days and we get a bill for $600. We called immediately and were arguing that we paid when they did not see it on her account. This went on for 2 weeks because I was traveling. I finally went in there and presented my HSA credit card bill and they realized they charged and applied it to my account where I had a zero balance. So they took my money happily and kept it nice and safe for me. They said they would take care of it. 2 weeks later we got another bill from them and it had $150 charge on it. I took it to my office and planned on calling to see why there was a charge. That same day their precollections group calls my wife and she pays them over the phone (all the threats that collections does). I call in and blast them and told them that we tried paying in full on day 1 and their incompetence was the reason this all happened. I still had to pay but we are not going to CEENTA anymore. It was painfully annoying.