This happens to me frequently, I have an OG gmail account which a bunch of people have associated with their own accounts. The problem is the provider will verify a phone number, and once that's validated, will accept an email address, even if it's wrong. Two financial entities have accepted my email address tied to other people's account: Chime, and Venmo. There's no way to fix this since they all presume I am a customer of theirs, so the path to fix is to do it in their app. It is incredibly frustrating, more so when it's people who handles money do it. They should know better! The "We are not a bank (therefore not covered by banking regulations)" does so much work to cover their shoddy practices.