I dont think quality is the issue. Vinyl will draw if overheated.
If sun and heat drawed it and caused it to curl you may not get it back to flat. I would wet it down with wd-40 or linseed oil and rollit up the opposite direction for a while.
Thanks,
But I am afraid it must be the quality. It had a good but of curling before I left the trunk open. It has been getting worse just sitting in the garage. And as I had five of my friends parked beside me at the show with there trunks open also. None of there mats curled. Just mine. Granted there cars are GM's. But they all had new repo mats in them. Mine mostly curled around the edges, and the cut outs. Seems awful thin to me. First sunny day I get (has been gloomy for a week) I might try laying it upside down in the sun and see what happens. Thanks!