ABSAlute nonsense has tarnished my credit record

Absa has shown the worst customer service from hell, and I pose this with the atmost disgust after they have tarnished my reputation by referring my checking account to a collection agency for a balance that accumulated due to a stop order amount thet I had disputed with them of having no knowledge of where it came from. The feedback I got when I enquired was the it was from clientele. After enquiring with clientele they had no knowledge of this stop since could not even pick me up on their records. I went back to absa and told them to reverse & CLOSE MY ACCOUNT. This was last year October/November, to my amazement I recently received a call from Vericred collecting on behalf of absa. Absa tells me there's nothing they can do I must just pay up an amount I have ABSOLUTELY KNOW KNOWLEDGE WERE IT COMES FROM!!! Alternatively the can refer me to their debt management center of which I think its absolute nonsense and poor customer service on their part.