Bob bought a Samsung Galaxy S9 and he thinks it's too large for his hand. Leo says that larger phones are the future, as people prefer a larger screen to hand comfort. Bob also has hundreds of contacts on his phone that aren't his after he synced it. Leo says it's possible that AT&T or Samsung sold Bob a phone that was returned and hadn't wiped it before doing so. But if they sealed it up to make it look new, that's against the law.
Another possibility is that Bob was given a used SIM card and the contacts were written on that. That's even more possible. Leo recommends wiping the phone and starting over. He might even want to go to AT&T and ask for a new SIM. Leo says he may also want to return the phone and ask for a new one.
Could it have been Google contacts? Leo says probably not. Google has done a great job sandboxing each member's contact information, so it's very, very unlikely that Google contacts from another accounted bled over into Bob's. It's also possible that if Bob is a Facebook user, those contacts could be from Facebook.