Putrid Servic

My TFG account was handed over to DMC, when contacting DMC last year November I was given a settlement amount of which I settled and paid the full amount. Since December 2021 I have been calling and emailing ***; ***.z; *** even ***. The only response was from TFG to say that I have no outstanding balances with them. So what is the issue with DMC why am I not getting and answer. It has been 6 months and I am disgusted that you have not even attempted to reply on my emails. I want this sorted