Everyone should send these shitty people drawings of poop. Good ones, bad ones. Whatever your drawing level..... draw a poop, lable it with "poop" if youre not sure theyll get it and send it. That should get across that we collectively think they are shit.
These types of assholes usually have po box for their businesses at the very least. On their website they typically have some sort of mailing address under "contact us."
If we can get inundated with junk mail everyday from shitty businesses advertising I think we can return the favor on this one.
Edit - put the return address from the north pole