"Now central IT deals with it only. the few hours a week spent on email related issues have risen by a significant amount since office 365 was shoved down the throat."
Our departmental mail support load is up by a factor of at least 10 - we had to take on an extra staffer primarily because office365 is such a pile of shite compared to our previous solution.
To add insult to injury, imap resources are deliberately restricted on a per-individual and sitewide basis and if you exhaust the individual limits (ie, if you handle lots of mail, where "lots" = slightly above average), you'll find yourself locked out for 24-48 hours, whilst the sitewide limits are reached virtually every day between 1130-1230 and 1600-1730, making checking mail a hit-and-miss affair (the support desk's canned answer is "Use the web interface, not an imap client")
The whole stinking deal was a clusterfuck, took more than 3 years to implement, cost over 5 million squid and was probably sealed by a handshake on a golf course somewhere (the previous Provost announced the move to outsourced mail out of the blue and caught a lot of people by surprise, including ISD).
Whilst the old mail system was a tad flaky that was entirely down to overloaded hardware (which was fairly old) and 5 million buys a LOT of hardware. What UCL has now is significantly worse than it used to have centrally and an utter disaster for departments who used to run their own well-maintained mailservers.
The public accounts committee would have a field day.
Anon because I work there.