people usung my apple id to purchase iphones on credit
What should I do
Change your password and consider doing a name change. Also consider setting up 2 Factor Authentication
What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.
Apple ID -Two-factor authentication
Two Factor Authentification availability
Apple ID - Using app-specific passwords
Apple ID - Two Step Verification App Specific Passwords
