A friend of mine didn't update his copy of iOS 7 when any of the updates were released, so his copy expired on July 24th. For some reason it's saying his phone is "linked" to my account and it won't let him enter his own icloud info. Also, weirdly enough he tried to activate a completely brand new iphone after his phone was locked because he was eligible for an upgrade and it's still saying his number is linked to my account. I don't know why the new phone would be affected by this, I never logged into his phone on my account.