250MB used up within an hour!

I contacted the call center this morning to enquire about an unusual occurrence with my data usage, I recharged with 250MB of data this morning , within an hour and a half I got an SMS that my data has been depleted. I have been on two websites, flysafair and twitter, thats it! How could that possibly consume 250MB of data? The lady at the call centre was particularly blaze about the request telling me that I should switch off my updates and that it is because I use the internet!!!! I've been using this phone for 2 years, I have done no updates, I know exactly how much I consume. Please look into this, it is extremely unusual!