Servers can be deleted in the following cases:

1. Server was automatically removed after extended downtime
2. Server was manually removed by you or any user who has the ability to claim it
3. Server was banned from the site http://www.gametracker.com/forums/forum.php?site=1&thread=75205

We are not able to recover any stats that have been permanently removed. It is your responsibility to rectify any of the underlying issues that may have caused one of those.

You can answer the following questions to determine the issue:
1. Did you experience a lot of downtime? If not, cross out number 1.
2. When you re-add it, do you get a message that it is banned? If not, cross out number 3.

If you crossed out those three, either you or a user with admin access to your server deleted the page. There would be no other option.