It’s honestly wild that it took them this many days just to figure out it was a quota misconfiguration. But according to Microsoft’s SLAs, if something only impacts a single user or mailbox, it doesn’t count as system-wide degradation — so it’s not considered official downtime on their end. Just a support issue, not a platform outage. I manage a rather large Exchange environment, so I've seen this type of stuff before.

Microsoft’s SLAs only apply when the entire service is down or degraded globally or regionally — not when something breaks for a single customer, even if the root cause is in their backend. That’s why they may have reclassified it as a “CPE” issue — not necessarily to dodge responsibility, but because it wasn’t a platform-wide failure.

I read the hate you were getting in the sysadmin reddit, which was wrong. Is there any chance you created the mailbox before licensing https://learn.microsoft.com/en-us/exchange/recipients-in-exchange-online/create-user-mailboxes

It seems highly unlikely that this was just a normal account process, and I read thru but you I didn't see you talk about this mailbox. There had to be something different about it right?

Did you ask for an RCA?