Harassment for collection of settled account.

I am under debt review and has one of my Absa credit cards been paid off under debt review. My Debt Counsellor has sent Absa notice to close the account with proof of settlement. However, Absa keeps adding fees to the account and am I now being harassed on a daily basis (via phone calls, emails and sms's) by their collection agency, Anthony Richards and Associates, for payment of the "overdue account" . Myself and my debt counsellor has contacted them numerous times and provided proof that the card has been paid in full, but still I am harassed daily. I really don't know what to do. It has reached the point where I don't want to answer my phone so my colleagues won't overhear the conversation. I did the lawful thing when I realised I was in over my head financially and have been paying my instalments monthly, but 3 years down the line, I am now seriously being harassed and don't know how to get it to stop!