Check in the cargo area. There is a nut that lowers the spare tire on a cable hidden under a flap in the carpet.
If the tire does not come down all the way then the safety catch is stuck. The tire will come down a few inches and hang by the plastic t-bone holder. You'll need to get underneath the car and either reach over the tire or up in the center hole to release it. It is thinner than the main cable and hard to get at, but with some effort and good hard tug it will release.
It's a horrible design flaw.
After you finally get the spare tire off, you should either lubricate the release catch liberally or disable it completely so you're not stuck again.
I'm just glad it happened to me and not one of my daughters.