Handing over a paid up account to DMC

Since February of this year i have been trying to get the credit card debt collectors off my back and sent an email to ********** and my details to Refiloe Tshukudu from Customer Care. I am STILL getting SMS's from DMC for collection of debt on a number i changed recently so where they got my details from i don't know. I am now going to SUE both ABSA and DMC for harassment on a paid up account and the undue stress it is causing me. ABSA don't respond to email so maybe a lawyers letter and having to pay the costs of my legal fees will make you wake up!