Contacts and calendar no longer syncing between google and phone
Try these things:  


Go to the tablet's System Settings/Account (Google), tap your account name, make sure Calendar is checked for sync.
Go to the Calendar app's Settings, tap your account name, and make sure the calendars that you want synced are checked.


OR

Settings-->Apps--> click on the ALL tab-->Calendar.
Then Clear Data.
Then go back to Settings-->Accounts-->Google--> Tap on Calender for sync.

Short cut name will change according to which android version you are using.