How to unlink two iPhones are still linked after Apple ID change?

Question

I upgraded to iPhone 5s and gave my 4s to a friend. I reset it and everything but the iPhone still had all of my contacts and everything on it. She reset it, it didn't do anything different. She messed around and somehow got her email address connected to my apple iD. I sent her to the sprint store for them to help her reset it. They set the phone up for her but our phones are somehow still linked. I have deleted her email address from my apple account. It had it under the alternative address section. But when I go to send a text message and look up someone's number through the search, it brings up names and numbers that are on her phone, but not in my contacts. When I go to my contacts, they do not show up. Only when searching on the text message section. Also I notice that her email address is still listed in my icloud account. When I click on iCloud under settings and and click on my account email address it brings up my account info. But at the bottom it says "advance" and her email address shows there.  how do I fix this?

Answer 1

This isn't being cused by iCloud.  It happens when you both use the same Apple ID for iMessage.  To fix this you have two choices:
On one of the phones go to Settings>Messages>Send & Receive, tap the ID, sign out, then sign back in with a different ID.  Note: you can still share the same ID for purchasing in Settings>iTunes & App Stores; or
On both phones go to Settings>Messages>Send & Receive and uncheck the email address(es) shown under "You can be reached by iMessage at".
Also be sure you aren't using the same ID for FaceTime or you'll get each other's FaceTime calls.  If you are, one one of the phones go to Setings>Facetime, tap the ID, sign out, then sign back in with a different ID.