I own a timeshare which I want to get rid of. How can I do that?

I have 2 timeshares Real Playa del Carmen where I seem to get nothing I paid $3200 usd in sept and oct 2010 the other time share is Plaza Vacation Club thru Shell vacations based on a 5200 point system every year so far I have given them 5000 usd dated Oct 2012 with a promise of 300 for 76 payments.