unfair treatment/poor service

I was owing teba bank R7100 for loan around 2007 and paid off the whole amount in cash manually at ubank in carletonville and assisted by ubank staff to do payment manually till I deposited the amount at the tellers,but big surprise now is that every week I receive calls from Norman Bizet lawyers telling me that my account has been handed over to them on may this year.I'm so disappointed about ubank poor service and unfair treatment on their service.I'm not owing ubank any cent and they must make sure they fix their mistakes and clear my name from listing.