How to retrieve lost contacts after changing my Apple ID email address?
I have changed my Apple ID email and have lost some of my contacts, is there a way to retrieve?
[Re-Titled by Moderator]
Did you change your Apple ID mail address as explained in this article?
Change your Apple ID - Apple Support
And you also mad sure that the changes were updated on other apps and services as well?
What to do after you change your Apple ID or password - Apple Support
Are you syncing your contact information with iCloud?
If yes, did you make sure that "All contacts" are selected in "Groups", if you open the Contacts app?