Poor credit management and stressful process to get my refund or proper credit wipe

I went to a store in acknowledgment of my debt after a long period of unemployment and failure to pay, was told my account was handed over to Tenacity for management then the very same Tenacity sent me an email last week with bank details for me to pay, this week I pay full amount quoted to me in email when I follow up I am then told the account was handed to CSC last year then I visit another nearest store after tons of emails and calls and WhatsApp attempts to communicate this matter but no correction of this transaction has been made back to me or communication that Tenacity has maybe transferred the money back to CSC or Ackermans. This is very stressful coz I have a life I can not afford going back and forth to the stores only not to get any assistance or my money back. I’m really uphold!!!! And thinking of opening a case, I fail to understand how they handed me to Tenacity knowing my account has been handed to a different credit collection in the first place, worse Im now left alone to handle these debt collectors while I have an account with Ackermans!!!