Gold Coast Surgicenter

I had to pay $2,250 on September 21,2019 as my co-pay for surgery. The surgery was on October 4, 2019. My insurance company was billed on October 21, 2019 and they paid the bill on October 25. The Explanation of Benefits from Blue Cross said that I had only needed to pay $1,453.78. That means Gold Coast SurgiCenter owed me a refund of $796.22.I have called four times asking where my refund is, have have received four different excuses as to why it hasn't been processed (none having to do with a dispute of the amount they owe me). My most recent call was on January 28, 2020, when I was assured that the refund would get processed right away. It still has not been processed.
Reviews of this Surgery Center mention similar problems in getting refunds. If I owed them the money, interest would surely be charged.