How Do I Fix This?

There should be a 1/4" screw at each end of the track..make sure to remove those screw then pull the fabric to the point where it's still in the track. Then pull it back and either have someone hold the loose end or make sure it follows the rest of the fabric back into the track. Then reinstall the keeper screws back in and your done. Pulling the fabric out and then back in is the toughest part.

David