Blacklisted cell phone sold

I bought a cell phone from MTN klipmed in witbank.This was a cell phone upgrade, but the phone only worked for 2 days and then it started having issues. After several attempts to resolve the issue and taking the phone to Samsung in Benoni, I found that the phone was blacklisted. Mariah the manager of the MTN branch in Klpimed has since not assisted us and she promises to call but never does. Mariah claims that after I received the phone, there was a break-inn at the shop and they included my handset in the list of ****** items. I am now inconvenienced by their incompetence and the mere fact that I have not received any help from MTN and they make it seem as if it was my fault that they had a break-inn. The manager is a very much *********** manager and does go the extra mile to rectify her mistake. If she had consolidated her system, we would not be in such a state. This is supposed to be my work phone but now I'm phone less and the company is paying for this phone, which is not even there