Is intellectually property mine without a contract?

You "own" (i.e., hold a common law copyright in) anything you creat, with limited exceptions. One of those exceptions is the "work for hire" rule. If you create something as part of your job duties, or on behalf of your employer even if beyond your job duties, then that work "belongs to" your employer, UNLESS you have entered into a contract in which your employer agrees that the work is not a work for hire. It sounds like the exception applies in your case.

I agree that you generally own a common law copyright. Based on your factual situation, I would say it depends on what sort of content you put on the Facebook page. If it was merely business address, name, phone number, website and simple blurb about the business, then I would there is no "intellectual property" on the site to begin with. If you created original content for the business page, it could be argued it was work for hire, but if you did it on your own and were not directed or "hired" to do it, then its arguable that it is your work. Ultimately, if your former boss is demanding this information from you or threatening some kind of legal action, you should contact an attorney and meet with them to go over the specifics.