My wife sat on an unsupported bed and it came down hard, no one got hurt, except for my pup. The canvas tore some, particularly this canvas lining that goes into the insert tube thing that helps with climate control/security. I can sew fine, but I need new material. I can't, for the life of me, find this item for sale anywhere. Seems I should be able to find a big spool of it, it's easily torn and, hopefully, i'll be able to remove the torn stuff and sew in new material with ease, then pry open the insert tube and fit it back in, then close up the tube again. Does anyone know where I can find some? Thanks in advance.