oh crap if its based on your most recent bill I'm screwed my girlfriends been away so went way over the minutes allowed in my £35 a month contract.

EDIT:

Also I have just been on the phone to them and was offered nothing new or extra and told that I should try to regulate my internet usage more if I didn't want to pay the charges. here are my usages for the last few months:

618.446MB

784.989MB

1.033GB

525.992MB