I would like to lay a complaint about Mercedes Benz Umhlanga

I would like to lay a complaint about Mercedes Benz Umhlanga. Their service is absolutely shocking. We ordered a part from them which wad to arrive yesterday. Unsurprisingly we have had no word from them regarding the part. I tried calling them, to speak to the Parts Manager. Only to be left waiting for ages on the line, and them to have the call cut. They claim 'priding themselves on excellent customer service' This is a bad joke.