Where are they not visible? Only on the device or both on the device and online, like from a PC or laptop?
If you are only unable to see them from your G3 you may have to ensure that you have the account visible as an active account to be displayed. Open calendar on your G3, upper right corner open the menu, the three dots, from the dropdown menu select "Accounts (All caendars)". There you will see your active calendars. If the one you are trying to view isn't selected you will not see any of the events or receive any of the reminders.
As for adding events and them not being displayed. Again this could come down to selected accounts on your G3. When you press the plus (+) sign to add events take note of the upper left corner. It displays the type and name associated with the account you are about to add events to. Touching that will produce a dropdown menu from which to select what calendar the event being created will be added to. If for some reason you are adding events to
123@server.com but you do not have
123@server.com selected as an account to be displayed you will not see the new event. Attempting to add it again should produce a conflict of schedule, which would confirm that the event was added, just not visible because it's not being displayed.
If none of this answers you question please post back with more detail.