Discovery Health is ingnoring paying an outstanding Dr's invoice for 1 year.

I have been submitting an outstanding Dr's invoice to Discovery Health for the past year or so. The invoice is still unpaid and I don't get a response from ***, and I have also loaded it on the app. I need the invoice to be paid ASAP. I am due for a check for almost a year, and I cant consult the Dr while the invoice is outstanding.