While they’re busy loading your bike, hop into their driver’s seat. If you’re lucky, maybe they left the keys in the ignition, free car! If not, either surprise the fuck out of them and ask “Where are we going?”, or call the law, or just beat the shit out of them, your choice.
You really dont.
At the point where he is leaving, unarmed and off the property. You’re pretty much 100% in the wrong and in this day and age catching an assault charge means you’re disadvantaged heavily for the rest of your adult life.
You let a petty theif get away with some petty shit for your own good.