all client reports delivered to a client

[hounds01]

I schedule a monthly report in one of our client's account to be emailed to the client. They received their report & reports of ALL our clients.

How can this happen, I spent an hour checking through every part of the plesk interface in the system area to see where the problem could be but found nothing.

I have deleted this sheduled report out their account but need to know why this has happened so it won't do this again

please help