Poor service

My sister recently took out a contract at Mtn Maponya mall, she has had this phone for 4 months and the phone is no longer working, the issue is when she went back to the store they told her that they have to fix it, there's nothing else they can do, she was then told that she might get the phone within 8 weeks, she was also give other options like opening up another contract to get a phone on top of the one she already has, another option was that she takes an upgrade of which the manager then said its too early for her to make an upgrade, my sister doesn't want this brand anymore she wants something else, because she didn't break the phone and secondly how is one supposed to live a full two months without communication during this pandemic, the service she was given was very poor, Mtn has to fix this because we will not take the phone back.