^^ The file Cleanup Policy is rather clear and Video is willing to help you out.

In the future, you should store your things in a chest in a town YOU own with a chest-access -g non_members deny flag, to prevent people from accessing it EVEN if you are absent during an LWC purge, every December - which depending on how inactive you are will remove your locks.
You can also store items in PlayerVaults or Travelbags to also avoid any file cleanups.
Store ECD on the forums to also prevent loss of ecodollars to inactivity.

To avoid your towns from being claimed you can purchase an UnClaimable App for any town you are official owner of. Or simply ensure you show your face around here once every 4-5.5 months to keep the activity requirements at bay for Town Claims.

It is literally only your in-game server balance, your inventory and your enderchest that are subject to the File-Clean Up Policy

Just some tips for you to prevent this from happening to you again :)