bad service

I am a very unhappy client of MTN due to covid I could not repair my cell phone only after the lock down restriction I manage to repair my phone and try to activate my sim card to my surprise my sim was deactivated and someone else is already using my number I had this number for over 20 years i reported this to customer service via email I received an email from Ofentse asking my number an email I rep**** via email its been almost 2 weeks no reply from Ofentse whats so ever this person that using my number is receiving all my sms and my banks messages