Lost all my photos and videos on my iPhone 4

I just bought an iPhone 4 yesterday at Best Buy and they ported all of my photos and videos to my iPhone from my android. This morning, I went to open my photos and they were all gone. I don't have a computer so I haven't plugged in my phone to a computer and I don't have access to download any software to restore my photos. I have important videos on my phone of a cat that passed on a week ago and I really want these videos back. I've never backed up my photos and videos and I sold my old android to Best Buy so they wiped everything out when they saw that the videos transferred to my new phone. Is there anything they or I can do to recover these photos? I have no clue where they went.

Added (1). I have no clue why the pictures and videos were gone. My phone froze for a little and I had to restart it but that was after all of my pictures were gone.

Added (2). The photos and videos were missing yesterday about two hours after I bought the phone but I just figured they were somewhere else on my phone and I never looked into it.

OOOH. You said THEY ported them, so its not on your computer. I don't think they'll have your " synced/backed up" photos or videos but It's worth a try. Go ask them if they do. I just thought for like 3 minutes WHY the photos would just disappear from the phone like that, and I came up with nothing. Never happened to me in my entire life. If you want to learn how to back up photos and all correctly you can visit my YouTube channel @ "Ihackpr0" and just watch the beginning of one of the vids to see. Other than that, best of luck for getting those videos back. I would be very depressed if I lost a video of my pet passing away. :L