Customer Services: https://community.giffgaff.com/t5/Hub/ct-p/hub
11 Vine Street
giffgaff launched in 2010 and are owned by the Telefonica group who also own O2. They work slightly differently from traditional networks in that there are no tie ins and your minutes, texts and data come in the form of goodybags which last for 30 days. Since 2014 they have 4G data at no extra cost.