Lost everything

So here is the thing, I have been with MTN for many many years, from the very beginning when cell phones were introduced. I have had my number for a very long time and alot of my accounts are link to this number for security purposes such as receiving OTP's etc. In the beginning of this Pandemic my phone gave me problems so in the process of switching sim cards from one phone to another, I had lost my SIM. i cannot do a SIM swop myself as its on contact which has no come to an end. The account is on my mothers name and she is an elderly fragile lady who cannot take the chance to venture out in public with the virus around. I cannot do the SIM swop as the account is in her name and I cannot even port my number to another provider. There is an amount outstanding but with not being able to leave the house at that stage we were not able to work and not able to generate any money. Now, after 4 or 5 months, I am trying to get this back on track again but I cannot without my number as I need the OTP's to access things. I have already lost access to my one bank account and I cannot do any of my banking anymore causing my Bond payments to fall behind as well as my vehicle payments. My Business domain has now expired as i cannot log in without the OPT sent to that number. So i have lost all my emails, i am loosing clients and work everyday cause i am not able to get my number back. Basically everything is going down just because of that SIM card and MTN will not issue me a SIM SWOP. Its a mess