Legal Question in Mediation in Missouri

If they left on their own (you didn't force or coerce then out), and you can prove up the lease agreement, you might be able to bar then from entering the premises until the unpaid debt is satisfied. It might be satisfied by then paying it, or possibly from the proceeds from seeking the stuff they left behind. You should consult directly with a civil practice attorney in your area, before keeping someone from their property. If you act wrong, you could be guilty of a crime and/or liable for civil damages.

Good luck