I can't do a sim sawp

I have been trying to do a sim sawp for two days now and I still can't. I've gone into the walker park branch n attempted it and the assistant assisted where she could. Now I need to reply to an sms confirming the sim swap n I can't so I called 808 n spoke to many people about the same problem n asked for help cox I simply cannot reply to the sms. Instead of helping me mtn keeps sending me the same and over and over n all I want is for the sim swap to go through. I was told that a supervisor can do it for me as USB but when I requested that to be done, no1 could assist me. I'm sitting with a phone now that I can't use until the sim swap is done. I need help PLEASE , there must be at least 1 person at mtn who know man what they are doing!