You may want to contact an Attorney for advice on the document. Without knowing what it says, I can tell you that usually you should never stop paying your rent if you are under the terms of a lease as you could be evicted. If your relationship is good with your Landlord you might ask them what is going on. Otherwise, I would seek the advice of a real estate attorney and make sure you take the document with you (they might just ask you to email or fax them a copy).
One attorney in the Miami area my office works with is:
Alfredo Garcia Menocal of Success Title - 305-553-3464 They may not charge anything just for a telephone consult.