Bad Paint Experience Builders North Riding

I purchased a 5l can of black Plascon Water-Based-Super Gloss Enamel from Builders Warehouse, North Riding store, earlier this month. The can was made of a softish white plastic. On the drive home through some windy roads, the can, which I had placed on its base in the boot of my car, tipped over. I stopped to check, and found that paint had spilt out. I rushed home to clean it up - which I could mostly do as fortunately it was water based. One side of the can had popped open and almost half the paint had spilt out. One would expect a brand new can of paint to be completely sealed! I called Builders North Riding after I had cleaned up to inform them that I would return the opened can the next day. The operator indicated that I should have taken it straight back to them when it happened. But I was too stressed that the paint would dry before I could get it cleaned up. I took the half empty can back the next day, but Builder's staff were not interested in assisting me, intimating that the can fell over because I was driving badly. Despite the fact that they have a sign in the Returns Department indicating they want their customers to be happy, I left extremely unhappy. I then called the customer complaints who said they would follow up and get back to me - which they said they did a number of times, but I have no record of their calls on my cell phone. Eventually after following up numerous times the manager called me and said it was my responsibility to transport the paint safely. After I questioned whether the can could be faulty, and what Plascon were prepared to do about it, she agreed to raise it with them. However, they both ultimately denied any responsibility, even though at no point did ANYONE even look at the can. After being a customer of Builders North Riding since they opened, it's going to take a long time for me to trust their service again. They need to take a leaf out of Hirsch's book when it comes to customer service.