Depending on how much you like the reel and how expensive it would be to replace, you could degrease the threads, both internal and external, then use a few drops of epoxy to hold the handle in place. I can't guarantee it would be a long lasting or durable solution, but it would work until a replacement can be found. You'd have to decide left or right hand for certain, once the handle is glued in place you wouldn't be able to remove it.
A more professional way of repairing the reel would be to use a helicoil, but that process can be difficult and I'm not sure if there'd be enough material to drill out for the oversized threads.
Even though you don't have the receipt you should call Eagle Claw, they may honor the warranty, or at least give you the part numbers you'd need and refer you to a service center where you could order the appropriate replacement parts.