Client of ours just got upgraded to Office 2016 as part of their Office 365 Business subscription, great.
They went to reinstall Project 2013 which was purchased as a standalone product a few months back, turns out you can't. Standalone Microsoft products like Visio, Project etc are not supported with Office 2016 as part of Office 365.
Find this link:
Great - spend 15 mins on hold, get through to the answer desk, they can't process Business subscriptions even though the link says they can. They pass me off, I get passed off again and eventually hung up on. Lol.
Microsoft know how to make things hard for their clients.....