lost contacts after upgrade

I have lost most of my contacts after upgrading to IOS 10.3.2. To be precise this upgrade was a disruptive one, still struggling to rectify this issue by manually saving them one by one..Thanks to Whatsap which helped me to save few of them.. Though third party tools like PhoneRescue helps over contact restoration, license key has to be entered to activate the same. My concern is why isn't Apple has taken initiative to notify Users or create a tool like PhoneRestore to help them recover their contacts.. if upgrades are disruptive then Users would not proceed further and might end up running older IOS. I can still work and get my contacts back but you have lost the reliability factor.. Just have a think about it...

Regards,

Harsh