Total lack of service from MTN Cape Gate

On the 1st of July 2017, my phone LG K3 (7 months old and under guarantee) became faulty and need to be fixed. I handed it in at MTN Cape Gate my service provider who said it would about 5-10 working days. 15 working days later after no feedback from them I called telephonically. I was told that it was in transit from the repairing department. My son, who originally arranged the contract on my behalf (as I am a pensioner) started to make numerous enquiries with no results. The Manager said that she would contact us within 24 hours with an answer to its whereabouts. This never happened as she has never once tried to contact us. My son physically went to that MTN branch 4 times over the next 4 weeks to collect the phone when the branch said he could come in and each it was not there ready for collection. Eventually my son was put into contact with MTN HVRC repair centre by MTN customer care as they did the actual repairs to the phone and they confirmed with him on 8th September by email (9 weeks later) that it was delivered to MTN Gape Gate and personally signed for by the manager of that MTN store. My son again went to fetch the phone and he again discovered it was not there for collection as arranged. During this time he was corresponding with MTN HVRC repair centre. This has cost him over 2 hours each time off from his work. They started to be extremely rude to him on the email which has caused everyone a lot of stress. To make matters worse, on the 10th September, 2017 he discovered that the store is now closed for renovations. So how does he then collect the repaired phone? Another week goes by while he tries to get a contact name and person to follow up and speak to. but with no success. In the meantime MTN still continues to deduct for 2 months payment off my account while the phone has never been returned to me. It would appear to me by now that someone at MTN has probably taken my phone for themselves. Will I ever get justice here? As a pensioner I find that this treatment is unfair to the elderly. My son has tried to help me by taking time off from work but even he has hit a brick wall. What do we do? How can we get this sorted out? Does MTN not care about its customers? This also bad publicity for LG who's phone went faulty after only 7 months. Is there anyone out there who can assist me?