Poor service and lack of communication from claims department

I have submitted a claim for a 20-24 week scan that I paid cash for. The medical aid rejected it as their reason is it was not authorised. I am currently on the maternity program and it clearly states that I have 2 scans available especially the 20-24 week one. The invoice has the correct codes on it matching the maternity program document. This is very unprofessional. And creates such a hassle. Why bother making members register and then you guys don't process claims correctly. It is also very difficult to get feedback from the medical aid. This is supposed to be a stress free period but is causing me more stress than anything else.