FEDUP BIG TIME WITH TFG DONE PHONING AROUND

I had a outstanding overdue amount of R435.90 with TFG for my The Fix Acc i came into contact with them on 03.11.2020 to confirm this amount and get banking details. I came into contact with them again in December to reconfirm as i had the money to make payment they then told me that my acc was sold to DMC Debt collectors on 16.11.2020 and that i should contact DMC i contacted them and they told me my balance is R4103 which made no sence to me. I contacted TFG again and they recommended that i pay the outstanding R435.90 and send the Proof of payment to them. I then made payment and sent trough everything to them. I contacted them days later to confirm if they received my payment. They confirmed they received it and said my account balance was now R0.00 i then asked for a paid up letter. TFG then refused to issue me one as they say my account was sold to DMC... i phoned DMC and they told me that TFG should issue me with the paid up letter as payment was made to them and not to DMC. I then phoned TFG once more and they insist that DMC should assist me.... I have statements showing that TFG account is 0.00. I am being thrown form one side to another with no joy from either the two companies I know i do not owe another cent on the account. Why will they not issue me the paid up letter????