Did the coupler just come undone or did it actually snap in half? If it's the coupler, you could just order a new on if it is too damaged to put back on. Hope this helps!
Yes, a picture of it might help everyone understand as well. The models of double bladed lightsabers available are basically 2 lightsaber joined by a standard coupler or QR coupler. The QR being designed to separate (although on purpose).
Also, you could try calling them during 9/10 am - 7/8pm central time in hopes of reaching someone, although I can't say with much certainty that would be more beneficial. There is also the waiting game of just checking back on that email inbox every few days, they very likely have a post-holiday backlog of order inquiries, questions/concerns, and who knows what in relevant and irrelevant emails to sort through. Hang in there, hopefully someone here can render assistance in the form of a useful suggestion in the meantime, if it is in fact a situation that has a "quick fix".