Multichoice Greenstone

I had a PVR1 decoder that was faulty, They replaced it with a DSTV Explora on the 17th of April, I installed it that evening and had a few issues, I contacted the call centre who said I need to get the Dish re aligned. I got Aerial Excellence staff out on the following Tuesday costing me over R600, they tested and confirmed the new Decoder was faulty, on Wednesday the Decoder was returned, Aerial Excellence said they had no stock, I have since been their twice and phoned them to ask them to keep me a Decoder and to please phone me when they had stock. To date I have not heard from them and I'm still sitting without a decoder.