Never take an MTN contract, or you will regret it

I've been an MTN contract customer for 12 years until last year when I decided not to renew my contract with them. I followed all the required steps needed to end the contract at the specified end date which was 12/08/2025. I use a Samsung S21fe and it was working fine until the last day of the contract end date.

MTN has barred my phone from operating on any network. I called and spoke Noxolo and she advised me to take the device to MTN for assessment but she let slip that MTN might want me to get a new device which I have been saying I will not be doing now. To prove that they are using this tactics to get back on contract, I tested the Sim card on another device and it works perfectly fine. I don't owe them anything so I don't understand why they want to hold me ransom with my own money.