It's not about whether it's "legally" yours (and even that would be up for dispute) but how you acquired it. You can't threaten somebody to get things, that's extortion
> "Most states define extortion as the gaining of property or money by almost any kind of force or threat of violence, property damage, harm to reputation, or unfavorable government action."
Under your interpretation, if Alice took Bob's lawn mower without permission and refused to return it, and Bob told her he would call the police and report this unless she returned it, that would be extortion. The police coming and arresting Alice for theft is an unfavorable government action from Alice's viewpoint.
Similarly, if you were contemplating suing someone for damages over a harm you felt they did to you, it would be extortion if you told them you were going to sue to so unless they agreed to settle.