MTN - Get your accounts department in ORDER!!!!

Ok, so I do not have a problem with MTN directly. BUT, I keep on receiving calls and threatening messages regarding my account that is in arears.

So here is the problem, the account that is in arears is not MINE. It belongs to my BROTHER.

I did not sign for his contract in any capacity, So I need MTN to get their accounts department in ORDER and LEAVE me ALONE.

I have tried phoning them, sent emails and NOTHING is happening.