i was late for school once because my phone autoupdated with the wrong time, and i woke up 1 hour after my original alarm

either a. pull the battery, and let it pull the time again from their system
or b. manually set the time to the correct one.

if the new time is still wrong or it goes back to the wrong time after changing it manually... manually set the time to the correct one and turn off auto-update time.