Std bank is a sh*tshow

I made a payment arrangement with Std bank vehicle and asset finance to pay my outstanding arrears with them. The next thing the account gets handed over to Blake and ass. I make the same payment arrangement with them. And now my acc has been handed over to a debt collecting company saying that I did not honour my agreement with Blake and ass. I DID!!!!! I even paid the amount a few days earlier. I am tired of being harassed by diff companies and Std bank not updating my payments that arw being made. What is the point of making payment arrangements if I keep getting handed over