Was My Cell Phone Hacked?

Today I witnessed a troubling event on my cell phone. I saw the front display light up out of the corner of my eye, so I picked it up to see what was going on. The phone told me it had just received 49 Megabytes of data. I don't subscribe to any services that transfer data, and I wasn't even using the phone at the time, and this creeped me out a bit.

I called Verizon Wireless to see if they were pushing software over, or doing anything else that might result in this. I spoke with two people, and neither could explain. I suggested to both people the possibility that my phone was accessed without authorization or compromised, and neither of them refuted that possibility. On one hand I'm glad that they didn't try to dismiss the concern, because hacked phones are something I hear about on the security mail lists. On the other hand, I'd much rather that Verizon had been able to find the source of the data transmission in their own systems and explained it to me.

The phone is off, the battery is out, and I'm bringing it to be re-flashed sometime soon. I won't trust it until the existing software is wiped out and replaced with whatever is supposed to be there. I've got no reason to think anybody is interested enough in my life to do this, but I also can't afford to be wrong.