The veteran rewards, at least as far as they've been explained, are a one-time flagging. Once you've been flagged for the rewards for the first 30 days, that's it. Also, if you've already paid up front for the 90 days, I don't think you can 'cancel' and get your money back, you can cancel in so far that you won't get charged again after your 90 days are up, but you now have access to the game for 90 days regardless, unless you get yourself banned.
If you're regretting the changes you've made, I think you're SOL until they offer another means to get Fantasia.