Lost all appointments in calendar after updating to iOS 9.2 on my iPhone 6. How can I get them back?

Hi,

Check out the following links:

Get help using iCloud Calendar - Apple Support

Before troubleshooting, make sure you've made copies of any important calendar data from your devices and iCloud. Learn how to make copies of your calendar data.

Change the Sync settings for your calendars:

Tap Settings > Mail, Contacts, Calendars.

Under Calendars, tap Sync. If Sync is set to All Events, set it to a specific duration, such as Events 1 Month Back. If it's already set to a specific duration, set it to All Events.

Tap the Home button. Wait several minutes, then open Calendar and try to refresh your calendars again.

Jack