poor service

I cant believe I'm going trough so much with tgf group .I owed them they handed me over I paid them the 21 February 2019 I paid them the full amount that was owed to them 3 months down line I discovered my name is still listed I have proof off payment I have a paid up letter that I requested from the debt collectors I send that to Transunion just to find out that I am still owing tgf it does not make sense for them to send a letter stating I still owe them when I requested a settlement letter I paid the amount on the settlement letter .The paid up letter was provided now I'm struggling to get a job struggling to get a roof on my head just because of this .I have not gotten any response ever since I start complaining I will not stop till I get a response .