???? So much for the integrity of THAT company!
I once bought some defective heat mats from (I forget their name just now) a very nice little company. When I asked them about the problem, they didn't even ask for a receipt! They admitted that there had been a problem with a particular product and just asked me how many of the defective mats I'd bought and sent me replacements. No documentation requested. Nice folk, and when I remember their name, I'll come back and edit this.
Hydrofarm! That's the company. Black seedling mats in several sizes with green printing on them.