False sales pitch and after service

After inquiring about material for my new couches, the sales lady showed me material that she personally scratched with a fork. I was hooked that it should be perfect for my couches and 3 kids. After the upholstery I had the couches protective sprayed by a company recommended by the Hertex sales lady. During this process some paint got onto the fabric and so we had it removed with some vinegar and a soft brush. This fluffed the materiel up so much that it wasn't even funny. So after contacting Hertex they hen said that the guarantee expired because we sprayed the material ( which they recommended ) and that we should have used a sponge and not a brush. ( seeing a fork made no damage) So now once a gain the big company is pointing fingers to everyone else instead of manning up and owning the fact that they did not convey all the relevant info to us.