BSoD - Worst luck in the history of mankind?

So I started a contract with iD recently for an iPhone 5S two weeks into use the phone crashes onto a bluescreen and continues to loop indefinitely, sometimes coming out of it and other times not. I got the phone replaced and it went away for three weeks before they told me that they couldn't figure out how to fix it and gave me a new phone altogether.

I got that phone back today. Put my sim in, started using it again. Six hours later, the phone has just crashed to blue and turned back on again. I can barely believe my eyes.

People who experience this issue are such a minority that there's no way it could be a hardware thing, right?

I can't find anything that answers where this issue comes from, so I'm going to take a wild guess and say that it's probably being caused by my SIM as that is more probable than to believe that I am the unluckiest human being alive.

Anyone know what it could be, or whether there's a way to fix it that doesn't mean giving my phone back in and not seeing it for the next three weeks? Thanks!