Rubbish customer service. My SIM card failed to work despite 2 attempts to activate it. When I contacted them about this I kept getting messages back saying my account had no active SIM card (no kidding, that's why I was contacting them!) and therefore they couldn't help. I eventually figured out for myself that I had 2 accounts because of the 2 attempts to activate the card, so I started all over again contacting them from the other account. Their system seemed to have transferred my number to an apparently imaginary SIM card, which they suggested I put into my phone to solve the problem. Eventually they gave me some long-winded but fairly useless instructions to swap my number from the imaginary SIM to the real one - luckily it is possible to work out from the website how to do a SIM swap. It requires an activation code that's written on the bit of plastic attached to the SIM card when it's delivered - it didn't seem to occur to them that most people would long since have thrown this away. (Luckily mine hadn't yet made it to the bin.) The whole process took 9 days, and at no point did anyone at giffgaff admit that the company had gotten anything wrong or offer anything even vaguely resembling an apology.