Terrible service MRP account cancellation

MRP account was paid up in-store on 05/12/2024 where I requested account to be closed. I was informed by in-store staff that I should call customer centre ***. I called customer centre where I was informed I needed to cancel MRP mobile sim that I was not aware that I had on my account. I was transferred to mobile cancellations dept when call was ended upon transfer to said dept. I have called said number on 09/12 and 10/12 and call was on hold for more than 20mins. I am not able to cancel the MRP or MRP mobile contracts due to this incompetence and terrible service and therefore will be billed again for a contract I tried to close. This is unacceptable and poor customer service!