Checking your balance
To check your Pay & Go balance:
Press Hotkey 2 on your mobile phone
Key *#10# then press the call button
Dial 4444 for free from your mobile
Remember: you need at least one minute of calltime credit to make a call. When your calltime falls below this point, you'll receive messages reminding you that you are nearly out of credit. Eventually, you will be diverted to the O2 Top-Up Line.
If you're not sure about any techy terms, check out our jargon buster