Do supermarkets in SA have an influence on milk prices?

The prices of milk has gone sky high and you can pay between R 14 - R16 for 2 liters of milk. The farmers here also complains that they don't get enough for the milk and the middle man takes the biggest cut. Our competition commission in South Africa has also investigated price fixing in the milk industry and they found that the companies colluded and agreed on the price of milk. There was also cases where surplus milk was transferred from one distributor to another to stop the lowing of milk prices. There was also reports where surplus milk was dumped to stop the lowering of prices.