Assuming you do not have one of the springs broken...only the last few inches does not roll up you have to remove the frabic. There should be a hole to put a nail in on one end to lock the tube from spinning while you slide the frabic out. Holding the tube by hand remove the nail and rotate the tube probably two turns tighter and put the nail back in...slide the frabic back in and remove the nail.
If the hems on both ends are starting to fail/break have them resown while off. All four of my toppers had this problem and there was enough unused frabic on three of them to cut the used off to exposing the unused.
