Guitar cases take a real beating. They are made from plywood or chipboard with a vinyl coating called Tolex. They are not indestructible and when they do get damaged they need not be discarded. In one hour, you can repair your guitar case and have the handles and Tolex coating looking like new again.
Peel back any loose edges of the Tolex coating leaving approximately 1 inch of the underlying plywood exposed. Spray adhesive underneath the loose edges.
Press the Tolex back down with your fingers, smoothing it as the glue begins to dry. Work your way around the case until all loose edges have been smoothed and glued down.
Spray any bare plywood cracks with paint where the Tolex is torn or will not stretch back over the plywood. Let the paint dry for 1 hour. Wipe down the outside of the case with Armour All.
Open the case. Pull the velvet covering back on the inside of the case behind the handle until the back of the handle is visible.
Force the tip of the dykes between the handle and the case where there are loose rivets. Cut off the rivets. Pry the loose ends off the rivets from the front of the case. Pull the remaining loose ends out from the inside of the case. Pull the loose rivets from the handle.
Place the handle back into position on the outside of the case. Hammer the new post loops through the handle into the guitar case from the front. Spread open the post loop tabs on the inside of the case with the dykes and tap them down with the mallet. Use the hot glue gun to fix the velvet cover back over the handle on the inside.
Use the hot glue gun to fix any other loose velvet on the inside of the guitar case.
If your guitar case is cracked or split, which rarely happens, it cannot be fixed sufficiently to protect your guitar. It will need to be replaced.