Just follow the Given Guidelines to fix Google Calendar issues

Steps is Here ?

Go to SyncGene and sign up;
Go to “Add Account” tab, select Google and sign in to your Google account;
Click on “Add Account”, add and log in to your iCloud account;
In iCloud settings on your iPhone you should enable Calendar synchronizatio;
Go to “Filters” tab and choose Calendar sync option and check the specific folders that you want to sync;
Click “Save” and then click “Sync all .

By Following above guideline you can remove your problems immediately .

Website - http://www.equoesto.com/blog/google-calendar-not-syncing-with-iphone/