Within your year of absence a lot has happened. One major thing that has happened is the server merge between Gaia and Bodor which then formed the new server called Ponchee.
Another thing is the GM's did a clean out and deleted some characters before they physically did the merge itself. Characters that were below level 20 and had less than 1 gold on the account were deleted, except if you had a character above level 20 on that account, in that case you should have the amount of characters you had before the server merge. If you did have a character that was above level 20 on your account, the other character's should not have been removed. There were however, some issues that occurred after the server merge, such as characters missing, that might have happened to you. Submitting the ticket was the best thing to do as you already have.
The only piece of advice I can give you is to wait patiently for a reply from the GM's via the ticket you submitted. The reply should take up to 48 hours, But the GM's are usually pretty good and respond before that, usually the next day. If you do have any other issues on your account, I suggest you submit another ticket separate to the one about your missing characters.