Their Negligence clients fault

I called African bank to get settlements on outstanding debt the lady provided me with settlement amounts I then asked her what about the credit card and she confirmed it was paid up and I dont have to pay she provided me proof and I just paid my other accounts, 6months down the line I pick up a account on my credit report just to call and find out its african bank credit card I owe I informed them I have proof that they said account was paid up ,know the company that they handed me over to says according to African bank this account was never paid up whoever send.me the paid up letter they not sure because they never received payment and they need proof of payment I explained my case and said i did not pay account but was informed I dont have to cause its paid up. African bank refuses to take responsibility for their Negligence wants to keep.me liable I refuse to pay this account and now they want to bring up clauses and terms this is the worst company ever and I will spread the news to friends and family's