Poor service delivery

I have 2 personal loans with Nedbank and they were handed over to debt collectors meanwhile I have not even skipped any payments for both of them. One of the loan is fully paid up and I have requested for a paid up later twice on my bank app, I never received anything. I called in wanting to know as to why my loan was handed over to debt collectors and I was put on hold for +- 30 minutes and the line eventually hanged up. To my surprise Nedbank is still debiting the agreed repayment amount for one of the loan and yet debt collectors are instructing me to pay the loan on their account