Product did not work

I had seen this product at the Ideal Home Show and watched the demonstration of the guy removing a stain from his carpet, I brought this product on the basis that having seen it work fo him it would work for me, it says on the bottle that it works on rust and I checked this with the man at the stand, however when I tried it at home it didn't work atall!

I was really annoyed as this cost me £10 and with no receipt or website there is nothing I can do to get a refund for this item which doesn't even work!...