A long time ago I was in a relationship where my SO took my car and refused to give it back. I called the police to report it stolen and they said that since I had lent the car to her in the past, this was a case of someone not abiding by an agreement, and it was a civil matter and I would need to retrieve the car or a PI would. This was California, so other states probably have different laws, but I would have to think for a major corporation this should be in civil court first.