Supersonic's monopoly guarantees bad service

I was a SmartVillage client and received my analogue phone and fibre connection from them. At about 21 August myds IT guy checked with Supersonic that a Grandstream VOIP phone would work on their system. He bought the phone and Supersonic has been giving us a run around ever since. The reason likely is that they have a monopoly over the fibre in the area. To make it worse, we hear from the technical subcontractor who was here eventually that they have only received training in the phones that Supersonic sells. How is that for a monopoly? The supplier refused to take the phones back after a week, as supersonic took its time in responding. The base station and two handsets cost me R4 500 in total. I am a lawyer and am losing business because of this. I am thinking of complaining to the Competition Commission.