Came back yesterday (after years) and have the same problem.I ve sent a support ticket and
got an answer the same day.I am not home to check it ,but it seems theres nothing to worry
about.
Here's the answer.

"Hello there,

Your account was moved to our backup data due to long
inactivity. I just restored your data including sailors,
ships, credit/points and battle records, so you will be
able to play at your original server again. We're glad to
see you back!

Thanks,
zitroneGM"

Ok if your account is empty then it has been archived and saved.
Send a support ticket in to have the account restored.

Also note that the servers have merged and you need to be aware of
which one you are on now