My Upoints just vanished!

Maybe expired? AFAIK they are only valid for 24 months.

Edit: Just checked my account, 640 points.

when they made these changes i lost points as well. not that it really matters but still.
looks like them upoints cut too deep into their profits. pathetic...

As stated above could be expired, in that case they are gone for good
Or it could be a connection issue .. sometimes when you open Uplay you find both your level and points are zero but that is just means data didn't load up properly .. and in this case it is a temporary issue a restart of the app usually fixes it

Transaction history in Account Management should show if your points have expired
https://account.ubisoft.com/en-GB/transactions-history