Prosonus Eris8 Cone rubber

Anyone know there rubbers and own the Eris8. One of my kittens made a small clean slash falling off the top, and I'm looking to glue the edges, to seal and help it endure. I'm guessing it's just vulcanized rubber. s the glue from a puncture repair kit will work.
 
Prosonus are reluctant to tell me, as if I'm gong to replace a the whole driver and cone, and get the part shipped to Central Vietnam, and go t the effort of changing over a working unit with a 4mm cut in a non critical part.