Cashbuild cares less about their loyal customers

I bought Medal paints (Champion) at Cashbuild after the doors u bought at the same store became dirty. I paid a general worker to have them cleaned before he paints them. I have him the paints and the tools then I went to work. On return I was very tired and went straight to bed. I could smell fresh paint though and I was delighted. The following morning, I looked at his job...to my surprise all the doors were beige. I looked for the tins unfortunately he had thrown them away. There were 2 still unused and one that I could find. I took all 3 tins to Cashbuild and they opened the tins and they told me the paints were expired. I asked them the lifespan of their paints, they couldn't answer that. They suggested I leave the paints with them so they can speak with the supplier. I was called today for a replacement, 2 tons of Safari paint and not Champion. I couldn't take those 2 I left. How do I paint 5 doors with only 2 litres? I thought I was being fair for not wanting them to pay the general worker charges in the first place. I am sitting with their doors, beige in colour all because of their fault. The solution to this problem would be for cashbuild to take their beige doors and give me my white doors. I bought each of these doors for more than 300 at the same store. I built this house from scratch using cashbuild. Everything in this house is theirs. I'm their client since 1999. I've never come across such a disappointment. Beige doors!