You will be directed to a secure IP Payment website to enter in your credit card details
Click Top Up
Call *333 or 0800 323232 from your mobile
Simply follow the voice instructions.
(For credit / debit card payments you will be directed to a secure payment facility to enter your details)
Things to know
Once you have Topped up your phone, the credit will be valid for 12 months from when you first purchase the voucher. If you don't add credit to your phone within 12 months, your prepaid account will become inactive and any unused credit will expire. So all you need to do is simply Top-up your mobile at least once every 12 months to keep your prepaid account and phone number active.