Vodacom... unable to make contact, and they dont listen!!!!!

So my contract ended 31 October. so i phoned in July to cancel it and just go to prepaid. "No sir, you have to wait till it is end october" so i called again in october to remind them and change my banking details " sir it has been added to the list to be canceled"since then i got 3!! calls saying im able to upgrade, each time i said i have canceled it and they say oh i see here on the system. sorry about that have a good day.." Its JANUARY 2021 they still debit ordering of the wrong banking details, i had to pay the fine at first cause insufficient funds. just when i loaded funds to the account it went off again. FFS. Just make contact with me and refund the damn money cause i have followed all steps needed to cancel and change my banking details!!!