I would guess this person is dead, but if you're still leaving voice mails then that means someone is checking and clearing the inbox.

Either way, if they left it on your possession then died, and no one has come to claim it on their behalf, then they don't want it and it's yours. You can't be responsible to hold a thing in perpetuity until they get around to it.

Same thing if the person is actually still alive, lazy, and ducking your calls. They've forfeited ownership by not picking it up and not working with you.

Keep it and play it, or if that makes you feel bad, donate it to a boys and girls Club or a hospital or something. Somewhere that they would appreciate some entertainment and have only a shoestring budget. That's what I'd do in your position.