Bad service from Vodacom, they bill me after my contract ended

I app**** for a Vodacom contract for 24 Months and I never skipped any payment in August when my contract was about to end , I called them to remind them that my contract is ending and I have no intention of continuing , I was told I must call in September of which I did, I spoke to a male consultant of an Indian descent who refused to cancel my contract and I paid two Months after my contract was supposed to have been terminated, the consultation even went as far as calling me stupid for wanting to terminate the contact of which I believe it should have been terminate after the agreed period . I am being harassed by Vodacom saying my account is in areas for over 2k even though I am not receiving any services from them . They treat people with disrespect and no regard to humanity