I have worked a number of support cases where this script has been useful for pulling just about any data available from a user object. Ideally you will want to run this from a PowerShell window connected to both Microsoft Online and Exchange Online PowerShell modules.
This script prompts for the User Principal Name of the account to run against, it then works to run a series of Get- cmdlets. Everything is written out to a file for review.
See https://gallery.technet.microsoft.com/Troubleshooting-a-user-88f65f15 for a description and to download the script.