Being held liable for Virgin Actives filing mistake

me and my "friend" where convinced into contracts in 2015 and at the time my Annual income was R0,00. No credit check needed or proof of income and we where uneducated. His fees where subtracted from my account and we went to resolve the issue, I stood next to him as he filled out a document changing it over to his account. few years later after the account has not been payed. A debt collecting company contacts me. I email back and forth between virgin active eventually getting someone to tell me that they did check month to month and the banking details did change there but was never changed on the contract. They did cc this old friend of mine into the email saying that he will have to provide a bank statement. He obviously doesnt reply and I have no contact with him whatsoever. After waiting and asking them what the steps are from here they say that I will still be held liable for his contract. after one of the consultants confirmed that the banking details where different when they checked month to month, so there was a time they did debit the correct account. Other than that I'm pretty sure that when you are compliant to the NCA that you need to check the affordability of someone before just signing them up.