Nokia Lumia 520 Resetting Randomly, What to do?

Ever since I got my Lumia 520 it has been resetting multiple times a day. I've done a soft reset and a hard reset without installing any apps and it is still resetting. Two questions:

First, if anyone else is having the same problem and knows a reason behind it (I'm currently running the latest version of Windows Phone 8) It would be incredibly helpful. Others have stated it's a battery issue with the connectors, but the connectors are snug and the phone still resets even when stationary.

Second, With recent developments as far as Microsoft buying Nokia's phone division go, I'm not really sure where my warranty lies and who to get in contact about fixing it or getting a replacement. I assume you get your phone back relatively fast too? As this is my only phone, it's kinda a bummer to have to wait more than a day or two out of fear of emergencies with my family.

I've bought the phone last month from TigerDirect, but they have no return policy for it. It is the AT&T go-phone 520, so do I contact AT&T, Microsoft, or Nokia? Kinda confused, and I hope someone has a solution!