Data usage 800mb in two days..

Hello,

I am the owner of an Iphone 4S with a 2GB dataplan for over 4 months now.

Apparently, this month, my data usage is extremely high compared to the other months.

Monday, I received a text from my provider that I reached 1 out of 2 GB data usage.
I found this rather strange since I was only on my tenth day of that month's cycle.

A few hours ago, I received a second text stating that I reached 1.8 out of 2GB data usage. So on two days time I hit 800mb worth of data.

My internet behaviour did not change at all during these months except that last week I bought a few albums on Itunes (yes with the computer).

Afterwards, I synched those songs to the Iphone with my office computer. Yesterday evening when I bought my last album, I synched them from my computer at home, causing all the music to be erased and synched anew on the device.

Apple clearly states that this should not use any data when done so with Itunes synching.

I contacted my internet plan provider to pull up a data record of what has happened (yet to arrive).

Browsing these forums I checked settings like Icloud sharing which has always been disabled.

hoping that someone has an answer to this one.

Regards