I have just had to pay 32 pounds to get a new sim card as they have decided to upgrade their system from 3G to 4G and to top it all off they have told me that I will also loose my number. (13 for the new card and 19 pounds delivery fee). Don't believe the website where they say free 3-5 day shipping as the online assistant told me this was not possible...
Very disappointed to loose my number and surely if they are the ones upgrading the sim cards and no longer supporting the old ones they should at least have covered the cost. Had it not been for the large amount of credit I still had, I would have wasted my time staying with them.