Billing for expired contract

Good Evening.

My contract expired,in March 2021 after two years of having it along with another contract. As this time was approaching MTN came to me and offered me another contract which I obliged because they were helping me save money with the new data contract. They didn’t stop billing me for the one which had expired and I have told them/asked them countless times and they did no such thing. I am now sitting with a phone with suspended services of all things (both phone and router and phone services) because I was not willing to pay for something that had been suspended. It’s August and they are yet to help me as they say my file is with their legal team and they have no bearing on my complaints. Please help me on what to do going forward as I’m unreachable at work which is not ideal.