Who has admin rights for your business on Google?
If your mail runs through your Google Business and they have access, did you know they can set it up that all email accounts in your business can send a copy of back and forth conversations to any email address of their choosing? It’s deep in the Google admin panel, but it’s there.
I just set it up for a client who wanted to make sure no balls were dropped on transactions and to ensure they were covered legally on property task conversations. They also wanted to make sure that their agents are actually using the branded email instead of running it all through their personal emails. Most email client admins have some variation of this. It’s important if you change staff or support teams for your mail, etc. that you change ALL PASSWORDS immediately once you know they will be gone.