Chosen Solution

I lost my data including contacts and calendars from my iPhone 6 plus after updating to iOS 9.3, I have an iTunes backup, but I can’t not find the lost data I wanted from iTunes back, whether I can get back my lost data from my iPhone? Anyone who can help, please?

Usually they are iCloud synced so sign back in iCloud should bring them back. If not, erase the device and restore from iTunes or iCloud backup, if you have any. Also you can use some backup extractor to load data from local backups. (NOT RECOMMENDING ANY SPECIFIC BRANDS) If they still don’t come back, the data is lost.

Jesus christ. All these answers recommending third party software which will all most likely require you to pay after scanning when you want to recover the data.