Never stayed there but I would suggest you call the owners if emails are not effective. Are you giving them sufficient time -- personally, 16 days doesn't seem too long to me (unless you were promised a quicker return of your depsosit in writing).
If you are really sure there is a problem, and can't get it fixed with the owners, you may want to contact the site owners of orlandovillas.com. I have rented a home from that site and on their discussion boards I have noticed they take a personal interest in these sorts of issues.
Good luck getting it resolved.