How do I remove and phone from my iTunes account?

Question

My dad and I share an iTunes account. He only has a couple apps so he uses my account to buy them and update them. We both backed up our iPhones to iCloud and we both updated our phones today through iTunes. Now all of our contacts are merged together. I went through and delted all of his contacts on my phone and then there were also delted on his phone. None of my contacts I had before I updated my phone are there. How do I get them back? And how can I take my dad off my account and have him sign up for his own so this doesn't happen again? If this helps I have the iPhone 5 and my dad has the iPhone 3G

Answer 1

This is caused by using the same iCloud account on both phones.  When you do this any data you sync with the shared iCloud account such as contacts is merged and will appear on all devices connected to the account.  Also, any actions you take on one device (such as deleting contacts) is replicated on all other devices.  To fix this you both need to have separate iCloud accounts (you can continue to share the same Apple ID for purchasing from the iTunes and app stores). 
Decide which phone will be keeping the current iCloud account.  On the one that will be changing accounts, if you have any photos in photo stream that are not in your camera roll or backed up somewhere else save these to your camera roll by opening the photo stream album in the thumbnail view, tapping Edit, then tap all the photos you want to save, tap Share and tap Save to Camera Roll. 
Once this is done, go to Settings>iCloud, scroll to the bottom and tap Delete Account.  (This will only delete the account from this phone, not from iCloud.  The phone that will be keeping the account will not be effected by this.)  When prompted about what to do with the iCloud data, be sure to select Keep On My iPhone.  Next, set up a new iCloud account using a different Apple ID (if you don't have one, tap Get a Free Apple ID at the bottom).  Then turn iCloud data syncing for contacts, etc. back to On, and when prompted about merging with iCloud, choose Merge.  This will upload the data to the new account.
Finally, to un-merge the data you will then have to go to icloud.com on your computer and sign into each iCloud account separately and manually delete the data you don't want (such as deleting the other person's contacts from your account, and vice versa).
Since you deleted your dad's contacts from the iCloud account, unless he has a separate backup somewhere else, they're gone.