Iphone 4 bill problems with data?

It says my account used 100% of its data allowance for the bill and my dad says it makes the bill higher but how much more will it add to the bill? Will it allow me to use the phone features? And will i have to pay more each month if it stays at 100%

Seems like it will not allow you to use the phone features if you don't pay at the sufficient price… That means you will need to pay more to get the plan! You will need to consult with the iPhone service about this situation to know how billing works!