Failed Sim swap

I lost my phone than I bought a new device than I did the Sim swap,only to find out that they saying it got declined without notifying me.i called mtn several times to try and fix it but until now it not resolved.I spoke to the manager called Tevin and he said I should do it again with the consultant than he will approve my Sim swap within 30 minutes but he never did that now my life is stucked because I can't make calls to my family and my business because of the stupid staff of mtn