Telkom account complaint

I cancelled my ADSL account on 30/5/2018 at Telkom branch in Mosselbay. It was confirmed cancelled .-Ref no- ********** 43A. My old account no- ********** 614. Now I am being hounded by a collection agency for the sum of R1300 for a suspended account of which I am not responsible . Can you please help getting this matter resolved . Regards, Herby Evans