I'm trying to get this plastic support thing out of the back of my bag and the thing won't come out. What am I missing? It slides up about 3-4 inches and then hangs up so hard I can't budge it. Is the thing sewn in or something? They advertise as being removable but I can't feel down in there to see if it's snagged on anything. The thing has began to warp inside the bag and is making a buckled out spot and it's annoying the crap out of me.