Failure to pay claim submitted

On the 26 January 2016 I had to see Dr Porter. I had to pay the account cash and was told to submit it to GEMS for refund. Up until now I have not received anything from Gems not even a phone call. I have the Invoice with proof that the Account was paid by me. I need Gems to refund me asap. I have submitted the claim twice and even mailed them the Invoice too requesting payment. But with no luck. Please help in this case as this is highly frustrated not getting a response from the Medical Aid Gems. Many Thanks