Cosmonet+MTN_***********, Inconsiderate Unreliable Cooperation.

I was working for Cosmo-Net under MTN and my own personal number was linked to their OTP authentication system. I left the company 5months ago. Right now I am unable to do a simswap cos my number is still linked and locked to the MTN system. I've went to over 3 branches including their direct store in Morningside to no assistance. I have a chain of emails from MTN and Cosmonet HR and no one is willing/able to assist. Its been over 3weeks reaching out to them 👎. Why is it so hard and long to remove my number on their system? Should there be any *****ulent activities with my number i swear both companies will account!!!!