I would also say no. I have bought many a frags and have lost some in the process. For the most part I usually ask for a replacement when they are ready to frag again, but I always expect to pay. There are a select few that will let you have them for free, but they are in no way obligated to do so. For all you know the zoa frag could be thriving behind the rock work. I have plenty of zoas and mushrooms that dislodge and end up behind the rock, but I see them thriving. Just take it as a loss and try again later.