MTN **********ly blacklisted my phone and now its my problem

MTN has blacklisted my Samsung note 20 device on the 19/09/2022 and I am not even an MTN subscriber. I have tried calling the call center for help but for some reason they cannot and the team leaders are never available. I do not know what to do further they have inconvenienced me so much i have had to take time off work and go to the MTN store which still did not assist in resolving my issue. I will now go and open a case of ***** as I have no other option. When I call and ask them to check they who blacklisted it they cannot give me the info they insist I need an MTN number in order for them to assist me but how were they able to even black list it in that case? so they have **********ly blacklisted and and refuse to take responsibility