2010 Volkswagen Jetta: Dealer "unplugged" stereo but I can't figure out how

The stereo died one day, and it turns out it was was draining the battery (due to a short caused by a water leak), so the dealership somehow disabled power to the radio. The battery issue was fixed, and the radio remained dead.

At the time, they told me they "unplugged" it, so I assumed either they removed the fuse, or they physically unplugged the stereo unit. Turns out it was neither.

I just bought and installed a new radio, but I have no idea what they did to disable power to the radio. I called them and they don’t have any notes either. They don’t have time for an appointment before we take an unexpected road trip tomorrow. The new unit has no power to it whatsoever, just like the old unit.

Any guesses? Can the radio be disabled via OBD? If you were the dealer and wanted to unplug a stereo draining a battery, what might you do?