recently lost all my playstation plus downloaded games..
it turns out you cant let your plus membership lapse, at all. i shut off automatic re-subscribe to upgrade from tri-monthly to yearly. i was off subscription for 3 hours and lost 81 games to "experation"
after a lengthy argument with customer service, it turns out there is no backdating, reimbursment or help to be had. and i was even polite(honest!)
so keep my loss as a lesson to those of you that resubscribe with a prepaid card from a store, or dont have automatic update turned off. this is for the free downloaded games, mind you..however the games you purchase at a discount arent affected.