Checking balance with o2?

[Jack06]

Hi Guys
I've read a few threads about this but no definite answers.
On my previous phone Samsung G600 I could check my balance via 212 02, but it seems you can't send a blank message on the iphone, either you have to put a single letter or number in, or hit return then send. Either way the sending indicator gets almost to the end then pauses and says error sending message.
What's the deal?
Jack

[Jack06]

*Update*
I just received 3 messages with my balance,
Are the error messages that pop not really error message after all??
*Q Sex and the City music*