Troubles with buying from the guildwars shop?

I can't seem to buy the bonus mission pack because it says that
it doesn't meet security requirements or something...
I've put in all the details right, tried doing it 4 times, it just doesn't work.
Any ideas?
The only idea I've had is that it uses a different email to the one I try and pay with?

Best thing you can do is to contact support. They can help you better than we can.