Discovery Health Refusing to pay my Covid 19 Test claim

I took my wife for a covid test via one of the covid 19 testing centres (not Pathcare) and paid cash for it. This testing centre is a client to the lab they use for getting test results. The lab gives test results to the testing centre and the testing centre gives the invoice to me. Discovery is refusing to pay the claim to me because they say the invoice must come from the pathologist. Since the pathologist does not give invoices Discovery advised me to contact the testing centre and ask them to put the Pathologist Practice Number on the Invoice (which I did) and they are still refising to pay me my claim. I am tired of following up with them and I need them to pay me my money because a COvid 19 test with Discovery is a benefit.