Mission to cancel subscription

I cancelled my DSTV subscription early last year, I called 2 weeks prior month end to advice them to cancel my subscription as at the following month the agent who supposedly assisted me confirmed that my services will be disconnected month end. So now I have been receiving calls from a debt collection company by the name of Blake Amp Associates Dstv requesting me to pay an outstanding amount of R372.00 that I owe Dstv. I then called multichoice and the lady who assisted me says my cancellation is showing as pending I should go to a branch to get this sorted which I feel is bull**** what can a branch do different that a call Centre agent cannot do.

Can someone please urgently sort out this mess, coz I'm not paying nothing to anyone as I played my role by cancelling my subscription on time, but because multichoice employs stupid *********** people who cannot do their jobs properly the subscription is still pending.