I have an account `[email protected]`. My problem is people  occasionally send mail (some is work related and may have private information) to `[email protected]`. I have sent messages to the latter address to see if I get an answer, but no response. I tried setting up a "new" account with this address, but get a message saying it is not available.

My questions are:

1. How do I know if someone is receiving these emails?
2. How do I find out if this is a currently used address? (If not, can I retrieve these messages or setup an account with this address?)
3. How do I prevent my coworkers from repeatedly sending emails to the wrong, but similar, address? (Threats of physical violence haven’t worked.)