TigerIdol15

My friend and I have a server that we have worked very hard on. They were playing in the server, and then everybody just crashed. They join back, and half of the world is just completely gone. We had built a large school and extensions from it and it is just gone now. We don't know how to get this chunk back and I am really asking for anybody's help. We don't want all our hard work to be for nothing. Thank you. TigerIdol15