SIM swap

My mobile device got ****** a week ago. I contacted MTN to find out how I can get hold of a new SIM card. They informed me that I can buy a new SIM card at Checkers, etc. I can then contact the call centre to do a SIM swap (to be able to still use my current cellphone nr.). I did so, went to Checkers, purchased new SIM card and got home. Started phoning the call centre. When at last I got to someone, they transferred me 3 times untill I got to someone who can assist with SIM swap. After a very helpful consultant tried assisting me telephonically, he had to escalate the issue. He couldn't manage to do the SIM swap. That was on Monday, it's now Friday and I'm still without my cellphone SIM. I can't do cellphone banking or anything else that uses OTP, because all of the OTP's goes to my cellphone nr. I've emailed them, sent messages on Facebook and Messenger but to no avail. What else do I need to do to get my phone up and running!!! I need my cellphone for work purposes as well as I'm working from home during the lockdown. I'm very disappointed!!