Sindisa Salvage, bad service, bad products

I am extremely disappointed at their lack of customer service and integrity. I bought 2x5litres of paint from them and that has proven to be the worst mistake I have ever done in my life and waste of money. I opened the first 5l and poured the given mixer on it and it reacted badly as a results harden, I reported the matter to them instead of offering any assistance they are accusing me of all sorts of things. I opened the second 5l started to paint with it but it hardened as well 10 minutes as I was painting. I am left with no product, money but faced with arrogance with no assistance at all