Given your facts, it appears that you attempted to verbally assert an interest in the vehicle, but never followed through on the process by filing any formal written claim or opposition to what appears to be the forfeiture of the vehicle. There are procedures they need to follow, especially when there is a third-party interest (the bank). File a request for a copy of the forfeiture papers, get a copy of your plea paers to establish that the forfeiture was not a part of the plea, and consult directly with an experienced AZ criminal defense lawyer to determine what steps have been taken, or need to be taken to contest the forfeiture. You can also contact the bank to see what paperwork they have in regards to them asserting their interest as the third-party lender. Good luck.
DISCLAIMER I do not practice law in your State. This answer is provided solely for informational purposes only. This answer does not constitute legal advice, create an attorney-client relationship, or constitute attorney advertising.