Unofficial Servers are servers we do not control. This means that if you run into an in-game issue on these servers, you must get in touch with the admins to see if they are able to assist you.
If you yourself run the server, or have admin powers - you can make use of the admin commands to help restore the state of your tribe back to normal. For a list of current admin commands and their functions, please refer to the ARK Wiki: http://ark.gamepedia.com/Console_Commands
Some of the commands that you may find helpful in this scenario are:
cheat forceplayertojointargettribe PLAYERID - Forces the player specified by their PLAYERID to the tribe that the target entity or structure of the current player belongs to. (PLAYERID can be obtained by using the showmyadminmanager command. A PLAYERID of 0 will act as your own PLAYERID.)
cheat givetome - Changes the owner of the targeted entity (structure or dino) to the current player
cheat giveallstructure - Gives the current player ownership of all the targeted structure and all structures connected to it recursively.
cheat takeallstructure - Changes ownership of all structures of the tribe the player is currently looking at to the tribe of player.
cheat takealldinos - Changes ownership of all dinos of the tribe the player is currently looking at to the tribe of player.