Refusing to release certificate

I have been waiting for my permanent certificate to be sent. I had to pay R50 late fee which I did last year October sent them all my documents and proof of payment. They said 6 weeks and i should receive it. Still nothing every time I phone them they say that I still need to pay R50 but when I tell them I did they just say send us all the documents again and I have done this 10 times already. I still cannot get them to give me certificate. I even have a reference number for the payment. They just ignore my emails. I am so angry cause I just want the certificate I paid for.