I would open up a new FB account and leave it open for them to see with absolutely NOTHING in it. Every now and then go into it and put something random, the weather is crap today, my dinner was lovely just normal 'boring' stuff. No photos, no nothing and have your own one either totally off the scale private so they can't even search for it or else deleted altogether. hen they might leave you alone as they'll think they have access to your 'real' account.