You are able to post your questions about giffgaff and the service in the help section and someone will try to assist you. Giffgaff do not have a contact telephone number for customers to call them, and all questions are addressed to the community members.
Should your problem be account related you may be advised to contact an agent, but try here first so that you can be advised accordingly.
You may need to learn patience and study the guidelines and see that although you cannot phone giffgaff you can chat to nice people and get involved with the community and your problems will be solved in due course. Good luck.