SA Post Office Online MVL Renewal a complete disaster!

I am trying to renew 2 of my vehicles license discs using SA Post Office MVL. After accepting the quotation and paying for the renewals and delivery, my application is rejected with reason "'Vehicle registered in another province" this after selecting Gauteng and both vehicles being registered in Gauteng with GP license plates. There is absolutely no way to resolve this with their online system and there is no way of getting hold of them, How am I suppose to get my license renewals with this type of incompetence? Why offer an online service that is a complete disaster? Now I have paid SA Post Office for a service I will never receive and if getting hold of them to raise a query is impossible, I suppose I will never again see the money I paid for this service!