Ongoing terrible service

On 5 August I went into the MTN branch in glenfair Pretoria for an upgrade. They informed me that the new phone would have to be ordered and would take 3-7 days before the phone would arrive, but that they would call me. I returned 7 days later as I was not called-I was told that my phone would arrive that day or the next and that I would be called.Again I recieved no call & returned a few days later to ask what was going on-the sales lady told me that they are experiencing delays in deliveries & that they would call me, no one did. Only after insisting on an update did I receive a call the next day where I was told the exact same thing. A few days later I received a call from mtn reminding me that I'm due for an upgrade-i explained that I had been struggling with the issue for 2 weeks to which I was told that the branch will call me. No one called. After over a month of this I notified customer services who only told me that I can upgrade somewhere else. This service is not acceptable