Billing and contract cancelation

I cancelled my home Wifi month-to-month contract on 31/12/2024 and returned their device. It was explained that their technical team was closed at the time and that it would take a while to finalized the closure because the device needs to be collected at the store first.

I am now requested to pay for Jan 2025, and have no refund due to me eventhough an upfront payment for the device and pro rata payment was made upon take up in 2022.

I was told that this would be handed over to collections if I do not pay, and this can affect my credit score.

I am disappointed and feel misled/ misinformed and that MTN uses false advertising to market their month to month contracts.