It is a temporare use of the Database, that allow this feature, just like spam mail it will deleted after x amount of time, co keep the database clear, too much yank in the database... from eg. 1000's of players inactive or 100.000's of players, will hurt the server stability, especially in a field where it has not been invested into havind additional resources.

That is the long explanation told short, they wont know if you are coming back, so unless you have legit stored it on retainers and such, then it vanished into thin air to preserve resources.

I don't know what the time is for an ex subscribed player will be in the database, or if there is any limit on that though, to go a bit further with things.

Sorry for your losses