Unable to upgrade and change banking details

Dear MTN , I have been a customer for MTN for more than 10 years . App**** for different phones some paid off but currently i do have an active contract which am paying monthly without fail. My previous passport under your contract CN041767 expired, long time ago and i have new passport which i have been trying to update with MTN with no joy . I have been to Eastgate Branches, and Rosebank branches but both could not assist me with that . I have made calls to MTN direct trying to updated my details with no success. On Feb 11 2025 i spoke to Kimele.Soobramanian who assured me that my details where updated over the phone and today when i spoke to someone my details not updated. I wanted to continue and do upgrade and also do Debit order for the new contracts but still i cannot do that because of the passport issue. What should i do? I dont understand what is so hard to change my details and move on . Im so disappointed in this type of service RegardsTracelee***