Intellectual Property- Facebook

2 years ago I started a Facebook page for a friend who had just opened a new business. I was not an employee nor did I ever receive any compensation for my building and maintaining the site.
I registered it in my name, using my email etc. and used that page to promote his business to the point that it became his main advertising vehicle.
My friend recently sold his business and told the new owners that he was the owner of the page.
My question is, who owns this page? I believe that I do, the new owners think they do.

I looked on Facebook already, and saw no items that answered this specific question.

would be good if we could see the page you are talking about

Did you set up a business page under your own personal profile or did you set up a second personal page for the new business?

You own the page - right up until the point that the new owners contact facebook and take it off you. It's not your business, you don't have any right to use the company's name, images etc. etc.

I'd advise you to delete the page and forget about the whole thing. I don't think you should ask for money, as there's nothing to stop them doing what I just said above.