Refusal of registering birth of babies

I gave birth on the 17th of June to twin boys. Me and the biological father whom I'm engaged to went to register the boys. We have submitted my South African ID and my fiance's valid Nigerian passport. The lady then told us that his passport cannot be accepted.. Up to date no one can give me a logical explanation as to why we cannot register the babies under the biological father's surname. I was however told that it can be done at a fee of R7,000. Why?? Me and my family feel discriminated by this treatment. I feel that because my fiance is a Nigerian they want to exploit us for money. I refuse to just accept this.. I need our boys to be registerd.. I insist they carry their fathers surname.. We have all valid and legal documents.. why is this such a big issue to to be simple birth registration. Our boys are 2 months old .. yet not registerd. This ************** cannot be tolerated at all. I need answers and action. I cannot believe that to register 2 little babies can be such a big issue

How do we solve this simple basic request??