Canceled my account but still connected and is billed for it

On Black Friday November 2022. Rain had a special for r1 a month for 3 month. So I said to my self ill take it for the children as I'm unemployed and only get a sassa and then by the new year get a job. To keep the wifi. So December came they send me a bill of almost 1000r I phoned to cancel because it's not what they said I will pay I'm only to pay 1r a month for 3 months. I have send email after email I have phoned in to cancel the wifi but still its connected and I dit receive another 2 bills for almost 1000r. This is not fair in a way they are keeping on the wifi and is still sending me the bill. Please help me cancel this account I don't want to work with them