Stop blacklisting people that paid you

I settled my loan in march 2019.I was given a discount should I settle in 31 days .of which I paid ,now am expected to pay the amount I was discounted on .they even debited my savings account which I had to fight for it to be resolved .it was paid back only in october and they still went and blacklisted me .I went to a branch in west mall but no one could help me .the managers were in a meeting and I sat there waiting like a lost puppy until they told me I should just pay the amount and get it over and done .they took my numbers to this day no one has called me *** ,***