Idiot working there

Since July 2016 I try to rectify a problem where MTN upgraded me with a new handset, which I didn’t receive. To keep my story short I decided that I will no longer pay my account till they rectify the problem and reimburse me for money already paid by me.. For obvious reasons they cancelled my contract and handed the account to Hammond pole, where a idiot, Christopher Ngqongwana, told me I need to do write a statement where I state that I never receive a handset and to be stamped by SAPS, which I did. By this time I already send the letter twice and still this person who don’t know how to do his job threaten me to black list me.