You'll actually be categorized as a Premium player rather than pure F2P. You did spend money. Also former VIP dropping to Premium retains some VIP benefits on characters played while VIP. A F2P players who spends some money to move up to Premium would not get these, so you're in pretty good shape here.
Originally Posted by renius2009
When you first log in you may have to select some of your characters to be locked. You'll be able to play 3 characters, plus one for each additional character slot you purchased, if any. If you only had 3 characters or fewer, then no impact here. (Character limit is per server, not overall.)
You'll have access to all your previous gold and storage and swift travel. If you create a new character it will be more limited than your old VIP characters. You'll have AH access, but it may be more limited than when you were VIP - can post fewer items. I'm not sure of the details on that though.
You'll only have access to quests in the content that you purchased, if you purchased any expansions like Moria, Mirkwood, etc.
Easy enough to just (re-install and) log in. Just be prepared in case you need to select some characters to be locked at the character selection screen.
Cener, Ingo, Rilibald, Hesred, Halras, Loringo
Arkenstone (ex-Elendilmir) - The Osgiliath Guard