Hey matboud! To be honest, the initial step you tried would have been the same one I would have tried myself. If the previous devices are still showing when you log back in after reinstalling, then it sounds like we still need to remove them from your account on the back end. The only thing I can think of trying to see if we can avoid having you Contact Us is removing the cars themselves within the app and adding them back in - did you already give that a shot?
Hi there matboud! Just wanted to check in and see if you'd had any luck removing the cars from the app or if you'd been able to reach out to have us unclaim the Sync on our side. Is everything working out OK?