Sim swap complications

I am being frustrated to do a simple sim swap thing. The whole process is very frustrating and complicated. I have tried several times with no help. I have also tried to call 135 number but it's not helping. Can some1 from MTN call me on *** urgently because I use that number for my business or *** (I need to retain my old number *** because I lost my phone recently) I have tried to get help from MTN Gandhi square yesterday and the gentleman who assisted me did not even want to listen to my story, he just told me to call 135 despite me struggling to complete the process. I am not happy at all because I have re**** with MTN for years buying air time and data and I did not want to change service providers but now I feel like being forced to end up migrating to other networks