Why android download 10mb every time I turn it on? [on hold]

I have a Samsung GT-I5800 with android 2.2 froyo.

Since 15 nov 2014 android download about 10Mb every time I turn it on. Some times download another 10Mb during the day. I turn off my mobile every day.

My phone bill increased 5 times last month.

I installed traffic counter, but I don't see any app that download 10 Mb.

My mSD external memory card was failing. I dismounted it and took it from my mobile. Yesterday android didn't download 10Mb, but today download again 10Mb after turn it on.

I would like to know which app is responsible and how to stop download 10Mb every time I turn on my mobile.