POLMED:MEMBERS MUST PAY UPFRONT BEFORE BEING HELPED???

Ref 020326QFMND6.Good day.I am unable to get straight forward answers from Polmed. I want to know why my mother who is also a member of Polmed must first pay for a scan at a service provider(Bayradiology Port Elizabeth ***)Service provider says because my mother is on aquarium plan all services must be paid for first before they will render services.This is not acceptable and Polmed must adress this.Where do Polmed think members must get thousand of rands from to pay upfront??