Customer Service - 1-800-345-SONY (7669)
Account & billing Support -1-877-971-SONY (7669)
Available Mon to Fri 8am - 8pm PST
Live Chat Available Mon-Sat 6am-10pm PST & Sun 6am-8pm PST
As long as you remain a PS+ subscriber, the PS+ games that are free are free. Otherwise, those free games you had downloaded as a subscriber are completely gone if you cancel membership. PS+ games you purchased while a member will all remain on the HDD if you cancel since you paid money.
EDIT: I misunderstood, but hopefully what I wrote above should come of benefit to others, LOL.