Your account can be easily compromised, then Mercari quietly "notifys" the public about the breach without actually providing details or corrective actions and the fraud department is subpar. They have a number where you can call and leave a voice mail or you can submit a complaint online and they give you a timeline when they think they will reply which isn't accurate. Thankfully I have a bank that is working with me on the app breach because Mercari certainly does not care.