I think people join giffgaff and then don't read through the terms and conditions properly. I have been barred temporarily beofre now and appealed against it. For me, giffgaff is the best network I have even been on, and I have been on quite a few!
I understand it can be frustrating and giffgaff isn't for everyone!
But it is for me
Don't forget to accept a solution to your post if you have one, and don't forget to kudos others who have helped you out