You can be inactive for years and still have an account. If you can't access it now, you may have been hacked. Just keep in touch with support and they'll help you get it straightened out, but it may take a few days.
you can check your gw folders (if you are on the same computer) and see what you find there--you might have kept some screenshots which may help you remember your account name or character names.
Though its best to wait for support to get back to you as long as you remember your login (email addy) and have proof of ownership (copies of the keys etc).
just a waiting game from there for support to get back to you.
and to answer the first question--nope, you can go years without logging in and your account should still be there waiting for you (my brother in law hasnt logged in in 2 years--still in our guild...)