MTN not assisting on **** related matter

I was ****med via a sim swop being done on my mtn number. My Bank requires MTN supply me of proof a sim swop was done by their forensic department but the only humans I can access claim such a department doesn't exist, while my bank insists they do. When I phone the head office they either hang up the phone or put me though to the useless 136 number which doesn't have any options remotely close to being able to assist me. I simply require them to send me a letter stating that indeed this **** sim swop was done but nobody seems to care in the slightest about this life altering money that was ****** from me.