Sorry to hear. When I was off-roading in Utah a few months ago, someone tried to steal the spare tire off my Taco's tire carrier. It's probably because it's still brand new. It's secured by two lugnuts and one wheel lock. The thief was able to to undo the two lugnuts but not the wheel lock. When we returned from our hike, and started driving, I could hear some type of rattling noise coming from the back so I pulled over to see what it is and yep, the spare tire was loose as it was only held on by the wheel lock.
I know many auto parts stores sell replacement lugnuts and even some tire shops sell it too but we were far from those places so I just added some bungy cord reinforcement to stabilized it until we get to town. I ended up stopping by a Costco's tire center to get two lugnuts. They have a wide variety of lugnuts and sell it individually. Costco charges between $1.50-2.50 each depending on your vehicle's brand and model so it's very reasonable.
Like I've said, I've never had to use the spare so it's still new, probably why the thief wanted it and thought it was an easy target without realizing one of the secure point has a wheel lock on it:

