Contract ends but Vodacom still wants to charge

I have a contract with vodacom, it's supposed to end on the 28th of January 2020,since the last week of December 2019 I have been to three vodacom stores trying to ensure that I have not made a mistake on dates, in all three instances the stores were supposedly offline and I must call the call center. Today on my second attempt I got through to vodacom, although it's stated on the website when the contract must end I must now give vodacom one month's notice to cancel a contract that is ending. The consultant I got through to Denise, like the three stores I have been at was far more interested in getting me to extend my contract even after I had expressed that I am not interested. I even asked, if died today, at the end of the month would vodacom continue to charge me for data I would not be using? And she rep**** yes, I don't understand the logic, why must I give additional notice on a contract that's ending? Why must I be forced to pay for a service I am no longer interested in? It doesn't matter whether I'm paying R2 or R2 million a month, why must I continue to pay for an expired contract Vodacom?! , why?! With the longest reference number available ***