eM client syncs my mails without my permission. How can I make it stop, and reverse the situation?

Hi. I connected eM with two email addresses so far. For some reason, it has deleted 99% of the emails in one of them, and in the other it has synched without my knowing, resulting in overflooding it with all subfolders I added from my database. What is going on? How can I sync back the the first one, and how can I avoid him synching the latter?