That is just plain old theft unless they can prove an owner sold it back to them. It's goods on the bill of sale. Owners can remove property while in possession of the car but if Tesla was not the owner after it was sold new, they can't remove it, and unlike other goods like wheels or a stereo the dealer can't remove it themselves - Tesla removed it without the owners' permission. Which is the legal definition of theft.
Bitching and complaining won't make them return what was stolen but a police report and a letter from your attorney may help.
Tesla bought the car back as a lemon buyback (they could not repair a door ding within the 30-day lemon law window and instead bought the car back from the first buyer), and I got a scorching deal on it. After the buyback, they sold it at auction to a used car dealer, and that is who I purchased it from.
Within 1 hour of buying the car, I took it to the nearest service center for a SW upgrade (was still on V9), and they printed out the config on the car for me, which clearly shows EAP on it, but it wasn't active on the car (only Basic AP). By the time I am able to drive it across the country and check with my local service center, it shows Basic AP now on the same config sheet.
Essentially, they sold it from the auction house to the dealer with EAP in the spec sheet, but already removed it from the car. They refuse to turn it back on for me, and given that I paid 45k for a fully loaded P3D with 230 miles on it, I refuse to pay $7k for FSD, so we are at an impasse. I still consider FSD a gimmick and not worth the cost, and the only real function I want is lane change on AP. I will never use advanced summon, etc.