Thank you. I have a P plan. I did change the retention default strategy, and applied the following two rules: never delete applied to All and move recoverable items to archive (14 days).
I applied that custom retention strategy to my user (in his inbox configuration). Still, deleted items indicate that they will soon expire, which leads me to believe the settings are not properly followed by Office 365.
What bothers me is that I cannot find emails that are 38 days old in either deleted items or recoverable items or in any other folder. If I understand correctly, they should be recoverable for at least 45 days on default settings, right ?
edit: I just found a recent backup (jan 28 2013). I have for example an email dating jan 4th that is now nowhere to be found in the office 365 web app, not using the search in whole account, not in the recoverable items.
I'll try and compile a list of occurences.