Impossible to cancel an expired contract

I have tried to cancel my contract more than 5 times now and it seems impossible.

My 24 month phone contract ended last year (September 2019). I then tried to cancel over the phone which turns out is impossible even now in the year 2020.

Being overseas I am unable to make it into the stores to cancel in person which some people can't understand. I was then made aware that my father is the owner of the contact even though I have been paying for it for the past 10 years. So I pay the contract and yet I can't cancel it. Another interesting point.

So I managed to get my father who lives in Durban to visit a store in La Lucia Mall where he was told that they couldn't assist with the cancel and he would have to go to the Gateway branch- which he did. After discussing with the lady in the store at Gateway she put him on the phone with the cancel department (Why I couldn't do this, who knows?). They told him that the contract would move to a pay as you go, and if this wouldn't be paid or topped up then this would terminate automatically. I have now received another statement saying that I owe more money with the contract price!!!!!!

How am I meant to get out of this contact? I paid the in arrears amount and then you keep trying to debit my account. Also which was cancelled over 6 months ago. So you keep trying to debit a closed bank account!

CANCEL THIS CONTRACT!!!

Account number: I***-1