All "unlimited" packages from all operators come with fair usage limits/caps so nothing is truly unlimited.
I'm on the Don for ages now and have never managed to put much of a dent in my 5GB monthly allowance. But I probably don't use it that much - some maps/navigation, browsing, email and a few other apps that are light on data...
Apps mostly, we don't have WiFi..
You know you can buy a data add-on if you use up your Don 5GB allowance before the month is up?
I still don't know how you use up that amount of data.
I don't think I even approach that on my home UPC broadband!
I didn't have wifi all during this year when I was living away in college too, so 3G was constantly on on my phone but I ALWAYS had enough... I was using whatsapp, snapchat, reddit, facebook and youtube constantly everyday ... what apps are you using, coz that's crazy its getting eaten up!