MTN not adhering to contract

I took a contract with MTN for two oppo cell phones that I was Supposed to pay for one phone as the contract stipulated. My Billing account is BA***. I took the new contract during December 2022 and my first payment was to be effected by January 2023. I paid prorata January 2023. The problem arised when MTN did not put two phone's in one account. They keep billing me for two phones instead of one and this is messing my financial goals. Every time I visit their branch in menlyn they always promise me a resolution and escalation and this is something that happens every single month since January 2023. Now my phone is blocked I cannot make calls. What I want now is just to unblock, tell me exactly how much I owe and sort out the agreement part.