Covid Test (PCR) refusal to pay out claim

My son had a (Covid Test) PCR test done at Dis-Chem for a pre-approved hospital admission. On claiming through Discovery they have rejected the claim due to the lack of Code C019 appearing on the receipt. This test was preformed on the 09 June 2021 and is the first test we are claiming for since the start of the pandemic. After Numerous telephonic calls reference numbers with Dischem and Discovery, Dischem who says code does not exist on there system and Discovery who are refusing claim due to lack of code on invoice and wont manually adjust due to auditors refusal regardless that they can cover hospital admission and portion of procedure and are aware that it is requirement for hospital admission. This experience is draining and unpleasant and has wasted countless hours sitting on phone. I don't understand how Dis-chem cannot know of the medical aids requirement as they say covered by medical aid on there website. And how Discovery just rejects claim in the hope it goes away even though it shows on there website that you get two tests a year from WHO.