Do not buy readymix products from Builders Warehouse

I purchased 2 bags of readymix building mix from Builders Express Greenstone Johannesburg. When we opened the bags, the building sand was very wet and a quarter of the one bag of cement was solid as a rock. Firstly, trying to mix wet sand with dry cement is a major task and very difficult. Secondly, the ratio mix of sand to cement is very important and if some of the cement is unuseable this could effect the efficacy of the finished product. Unfortunately I needed to have a job finished urgently and so could not take the bags back for exchange. Whatt I would warn other buyers, do not buy readymix products from builders. Their stuff lies out in the open whereas Leroy Merlin have all this type of product under cover and the price is similar.