Claim rejected since July 2020 with no valid reason

Good day, I have had a very terrible experience with this medical aid claims department, on the 6th of July 2020 I went to see a specialist upon a referral from a GP. I called the medical aid to get pre-authorization which I submitted before I went to see the specialist. However when the specialist processed the claim, I was told that the ICD10 codes are incorrect and therefore they rejected the claim and then the specialist resubmitted the claim only for them to reject it again saying there are missing codes whereas the codes are in the invoice. Another rejection was made saying the authorization was to an incorrect doctor and I have been calling trying to explain what happened and no one seems to know what's going on. I keep being referred to different departments. it has now going to be 3 months and I still have not had a resolution. it is almost like they find a reason each time to reject the claim. I am very disappointed and this service is unacceptable!!