Unhappy about new Samsung S8. MTN Waterfall Mall Rustenburg

I am writing this review on behalf of my father. In March he received a new Samsung S8 on his upgrade from the branch in the Waterfall Mall in Rustenburg. About 2 weaks later the screan of the phone went completely green, when the phone is ringing you cant answer. My father takes very good care of his phones, because when he did his upgrade, the lady who assisted hom did not believe the condition of the phone, because it still seemed brand new. He took the phone back to the branch. But now there is a lot of stories regarding this phone. Nobody can tell forsure how long it will take to get my father a new phone. The response everytime is just that he must come each week to find out if the phone arrived. On his upgrade he received 30 gig of data, and now he cant use it, because it expired. This is really unacceptable, we are clients at MTN for many years and I dont think this is the way to treat customers. Please can somebody help my fater. Please should you need to phone him, please phone after 15:00