Signed up yesterday , I was bitterly dissapointed with giffgaff. My sim wouldn't activate and I would only get 1 reply a day if I was lucky on their customer support chat system. This went on for almost a week. I bought a 15 pound top up and they kept trying to avoid giving Me a refund as I repeatedly had to re mention it as I wasn't prepared to pay another 15 for a voucher to activate my account. In my experience giffgaff are decent but their customer service is painfully slow and useless , you get what you pay for I guess.