I will be surprised if they send you a new one.
if they don't, you can cut out an inspection opening at the bottom near the tail end. You probably need an opening there anyway to add ballast to the rear in case the plane is nose heavy.
from that opening which should be big enough to insert your hand you can than flip the plane upside down, and after clamping the tails end from the outside, you can brush epoxy in the dorsal fin and maybe put some additional strips of fiberglass.
Also some of us build and installed formers in the rear of the fuselage to stiffen the body, since its pretty flimsy, so the opening can help yoy for that for the rear ones.
Hope you get your new fuse, otherwise you could try that fix.
Good luck.