Lord Dik
try to identify with which user u usually logged and progress ur account
then take a look if u have been changed of server in ur older account. to verify this, please on game take a look on top of ur screen where ur castle name and coordinates are and on right there is the name of the server: dark plains or untamed lands. click on the name and a new window will open with both servers and ur progress on them. you may be have been changed automaticly of server and then the progress seems to be out. so in that window you will be able to check ur castles. choose the right one and click OK.
if this is not the case and ur account has been vanished please contact support explaining all this and they will check what has happened and give you a solution.
you can contact support following this link
hope you can recover ur castle
Regards