Xperia X10 :: It Can't Take 2.3.3

S.E. sent a message stating an update was avaliable. I followed the steps and 2.3.3 was installed. Good I thought until I found functions on the phone no longer worked. After numberous calls to the moile provider I was finally told that I shouldn't have updated because the upgrade to 2.3.3 was not meant for my S.E. Xperia X10!Most of the phone now works but no WiFi (just says limited conectivity when trying to log onto home wireless) and no calendar.I can't seem to find a way to go back to the old version of the software either.