The answer to your question depends on the declaration of covenants and restrictions for your subdivision, the rules and regulations of the HOA, and the document sent you by the HOA. You should have all of these reviewed by an experienced real estate lawyer in your area. Your lawyer will be able to advise you of your rights.
Disclaimer: This answer is provided for informational purposes only, does not constitute legal advice, and does not create an attorney-client relationship. Actual legal advice can only be provided after completing a comprehensive consultation in which all of the relevant facts are discussed and reviewed.
If you live in a condo, it is most likely the rent restrictions are part of the declarations. If you live in a single-family home or townhouse and the association is governed under the Homeowners' Association Act, Chapter 720, then the only way they can enforce the rent restrictions is if they were included in the original declarations or possibly if the amendment to the declarations adding rent restrictions was passed before your landlord bought the property. Some courts rule differently on these matters and there is no statute governing the rent restrictions in HOAs. It's strictly by the declarations and if there is a valid covenant that was passed properly by a vote of the membership or it was contained in the original Decs.
This communication is not intended to create an attorney/client relationship. It is always recommended you consult an attorney in person to discuss your case. The Law Offices of Stage & Associates practices state-wide and represents homeowners and community associations. Please visit our website at www.stagelaw.com.