Vodacom does not want to cancel my 2 contracts that have expired with them

I called Vodacom to cancel my 2 contracts as they have come to an end. 4 consultants dropped my call just because I don't want to upgrade and the last consultant had the guts to tell me that because I'm not taking any offer hence they drop my call and she did the same when I told her that I can't afford to continue. This is the worst service ever and I have never skipped one payment over 3 year signed term with them. If someone does not want to cancel my contract today I will not be liable for next payment.