Last night a few of our customers experienced issues with not being able to see their balance or being able to activate.
This was due to problems with O2's firewalls. We weren't able to get our information through them and so we couldn't activate or display account information on an intermittent basis.
We did work on the problem to get it fixed as soon as possible but unfortunately it took longer than we hoped for and they were finally able to fix it at a quarter past one in the morning.
So our apologies for the inconvenience but be aware this is now fixed.
The giffgaff team.