Poor customer service

I ve had an account over almost 2 decades ago. Tried to apply for new account and was declined numerous times. Called customercare and was advised my was owing R600 and was handed over to realpeople. Contacted number only to find number is not in use. One of tfg consultants advised me that I need to pay direct to realpeople because debt was sold to them. After I paid that I should send proof of payment in other for them to remove my name from being declined always. How do I pay if I can't locate them? Why can't I pay direct to tfg? Is that debt considered prescribed? It's over 15years. Why m not given opportunity to to clear this? It's not even appearing on my credit score. I need tfg to remove my name to enable me to open and account