Covid test claim

I did covid 19 test after being sick and i had to pay out of my own pocket and submit a claim to Discovery. I submitted a copy of the slip and the invoice. The invoice state GG code : ICD 10, but they tell me they can pay my claim because the ICD 10 code does not appear next to the name of of the patient, instead a miscellaneous test code appear next to my name. The tell me i need to get another invoice with the code icd 10 next to my name. I have my test results, invoice and the slip, discovery is useless honestly.