BILLING 8 MONTHS AFTER CANCELLATION!!USELESS

I am being billed for a month to month contract which was canceled in may 2024 and I gave the rsm number and called in to cancel it after the device was handed in.

To date I am still being billed for this device and have been told by representatives at mtn customer support that the contract has been canceled months ago and im not getting billed yet other times I called I am told it is still active and was never canceled Rsm Number for cancellation and confirmation of handing in the router: ***-1 It has been 8 months that i have been getting billed for a service which i am not using and have no access to and nobody wants to help, if this does not get resolved within the next 48 hours i am going to get my lawyers involved!