BP fuel contamination

I put diesel at a bp garage in nigel sometime in September after that I went home, my bakkie stood for the weekend and on the Monday started giving problems , we found there was water in the diesel and damaged my motor. I've been in contact with BP sa several times regarding the matter, no one gets back to me about the issue and when I phone again I get told the tests results show no water in the fuel ,and I know the sample they had had water in it as you could see the water at the bottom. never again will I use a BP garage. my bakkie has been standing since then as it's really expensive to repair and I don't see why I should have to cover the costs.