iPhone app store chewing up data

Hello,

A while back I wiped my iPhone 4 and gave it to my mom. It's using iOS 5.0. She is not very tech-savvy and only uses it to make occasional phonecalls and receive a few texts. She doesn't have any social media apps or email accounts on it. She doesn't know her apple ID password, therefore she couldn't download an app if she tried.

A while back it seemed her phone was using up a lot of data, which was bizarre for her lack of usage. I installed Onavo Count on it, and it reported that her phone used 1.5 GB over the last 30 days... in the iTunes/AppStore.

What is going on?? Both the iTunes and App Store apps are closed.

Is Apple constantly pinging her phone to upgrade to iOS 7 or something? It's impossible to download apps over 20mb, and as I said before she is certainly not downloading apps (and her homescreen proves this).

This resulted in outrageous data charges for her phone that she was not responsible for.

I'm thinking the best option now is to re-wipe the phone and cross our fingers, but really... This has go to be a very serious issue on Apple's end that should be investigated.

Anyone know what's happening? Thanks.