TelkomSA - Atrocious customer service

A few years ago, I took over a contract sim-card from my sister, she was paying for it initially, and the debit order was transferred to me as I was the one using the sim-card.

In 2020 or so, my sister took a cellphone from Telkom Vanderbijlpark, using her own details, but it appears as though her Telkom account is still linked to my bank account because of the sim-card I took over from her. She asked that the banking details be updated to her banking details for the monthly debit order of the new contract, but that was not done. My account was debited for the duration of the contract, which was fine because I saw it as a gift to my sister. The issue now starts as soon as the contract has lapsed/closed, and my account is still being debited, Telkom even sent confirmation with reference ***7, but guess what, my account is still being debited.

I need this issue resolved as a matter of urgency, I do not have capacity to keep disputing debit orders, not only is it time consuming, they want to blacklist my sister because I keep disputing the debit orders.

You really need to do better TelkomSA, stop taking what is not yours! I hope this will be resolved urgently.