Since launching roaming in July, we uncovered an error which meant that some customers' monthly discount was calculated incorrectly. We've now fixed the problem, and any customers that were affected have had the extra discount added to their accounts as credit – meaning they’ll get an extra discount next time they renew.
What caused the problem?
When we introduced our roaming and international calling services this summer, we made some changes to the way your data allowance is measured to make sure everything runs smoothly when you're using the internet. To do this, every time you start using the internet, we reserve 150MB of your data allowance at a time: when you finish using the internet, we put the bit of this reserve you didn’t use back into your remaining allowance. This can sometimes take a little while to work, and we discovered that if your account still had some data reserved when your account renewed, our system calculated your data discount as if you’d used the whole 150MB, meaning your discount calculation could be inaccurate by a few pence. The problem has now been fixed to prevent this from happening again in the future.