App store using incorrect e-mail address as username - iPhone 6

I upgraded my 4s to an iPhone 6 yesterday at the Sprint store. They transferred my data from the 4s to the 6, then erased the 4s. Now when trying to upgrade certain apps (such as Find My iPhone, Facebook, Linkedin Youtube, etc.) it prompts me for a password, but the associated username is an e-mail address I've never seen before and has no association to me or my Apple ID.

This is making it impossible to upgrade the apps and it's frustrating to see someone else's address associate. I've trying signing out of Apple, iCloud and the App store both online and via settings, resetting the iPhone each time — to no avail. Please help!