Hi jojoliz
Im with 3, on 3GB per month. and if I get near the GB limit customer services told me I could pay something like 10p/MB or upgrade to a higher package for a month only, then go back down to your usual package.
However if he is on 5GB per month (?) then that maybe the highest package already so you might not have that alternative.
Youre outside your standard cancellation period and trhey havent defaulted or misled you so youre stuck with contract in my opinion. However Im sure this is just a running in issue as your nephew wont be used to managing his download level, and will now be more tuned in every time he gets a download box, this was the case with me. Get him to be creative about how he downloads, especially if there is alot of video involved - can he go and free wifi at McDonalds for example?!
By teh way - the one month I did go over it was because I downloaded an audiobook at 1GB, and by going over my monthly limit it cost me �60 because I didnt bother to sort it out, so get that dongle off him now lol!