MTN Refusing to Cancel Expired Data Contract

I have had a SIM card data contract which expired in 2023 October. I have been calling MTN asking for the cancelation of the contract. I have not used the data sim card but MTN call centre agents inform me that I must pay irrespective and then I must call again for to request the cancelation. Why must I pay for a service I have not been using and I have been requesting for cancelation. Even went to the MTN store and they informed me that they received a Whatsapp from the Head Office informing them that they must not assist customers who request contract cancelations.