No settlement letter / or balance, no payment!

I got sms, es, emails and calls about my son' s credit card which had a limit of R500. He got this Nedbank credit card while in University, so I was the one paying for it. As a student he didnt have an imcome, it was then my responsibility to pay it off. The credit card is handed over to nds debt collection company, I asked for a settlement letter and amount to be settled. They referred me to get the letter from Nedbank. I went to Nedbank to get the full settlement balance but they kept asking me about my sons whereabouts as hes the account holder. Honestly, if I dont get the settlement letter, i cant or wont pay that amount and interest grows on. I am the one responsible for that amount since he took the card while under my responsibility. In fact I do pay other accounts on his behalf with no issues. Whoever made the rule or law that i cant be helped to settle my sons account made it without considering all possibilities and factors. I went inside Springs branch so they can verify my fingerprints and my ID, or they could even call my son to check.

If I dont get a settlement letter emailed to me or my son's email address, that amount will not be paid... I tried, you dont want your money, maybe you should have listed me since I was responsible, not my son. *** ***, ***, and ***