my friend wanted me to put some files from my computer on his phone so he dropped it off and will pick it up later. but i had to install an app and he didn't have an account set up when i went to the play store so i logged on with my account. well, now it synced my contacts on his phone along with his contacts! i'm hoping there is a simple way to maybe "unsync" the contacts that were just synced to his phone. can anyone help me? thanks.