Its not that easy, once they decide to charge you they will give you 14 days notice, your bill then has to be 10% higher then it was the previous month, this includes any phone calls, text messages etc you may have used.

So its not actually that easy, you have to be careful, best way is to use almost 2gb of data, then they would have to put your bill up by like £15 to £20, you would defo go over by 10% then