Terrible claim service

I am assisting my elderly father who is getting very poor service from Sizwe. He recently went for an operation for which he did get the appropriate authorizations beforehand. He went to an associated hospital for the operation and made sure everything was in order on all fronts. His bills are not being covered for the operation, the reasons being many inaccurate excuses. For one, he went to Life Wilgers Hospital but because the invoice had a heading where Life and Wilgers Hospital were on two different lines, the claim was refused because it wasn't on the list of associated hospitals. That was corrected, but now there is another excuse not to pay. The surgeon is not getting paid, the anesthesiologist is not getting paid, the wound nurse is not getting paid. My father is paying a high premium for care that he is expecting, but not getting from the medical aid. I would like to sort this out as soon as possible.