@Michael1216 *IF* it is your SHARED space *AND* you have a GOOD reason (allergies, incompatible pets, etc) which disallow animals, then CALL AirBnb (or DM them using Twitter). You have every right then to have that reversed..."unconfortable with guest" or "broke house rules" SHOULD be the reason you state otherwise you don't have a chance!
HOWEVER if you just decided you didn't like pets AND he claimed they were "assistance animals" you will NEVER EVER be able to get it reversed. AirBnB sucks with regard to people that know how to game the system!
Jann