Sprint Katana phone logs on to internet by itself

when i signed up for sprint picture mail about a year ago, my phone began logging on to the internet on its own, causing about an extra $100 on my phone bill in one month. i had uploaded only about 30 photos onto the sprint website that month. tech support told me that if i carry my phone in my pocket then it is possible that buttons could be getting pushed. keep in mind that this is a phone that flips open so none of the buttons are exposed that could possibly log me on to the internet. so i ended up signing up to pay an additional $15 each month for unlimited internet access simply in order to avoid any more expensive surprises. even now, i make sure sprint pcs is disabled after each time i use it, but occasionally people will tell me that my line had a busy signal, and i will notice that my phone has been mysteriously silent and i will discover that the sprint pcs has re-enabled itself and must have logged on by itself. only once a few months ago did i actually catch it being logged on: one night when i was going to bed i went to set my alarm to wake up the next day and it was on the msn website. I don't use the internet on my phone other than to upload photos. it makes me angry that i would have to spend an extra $180 a year on something I don't use because sprint has a faulty product.