▸ giffgaff PAC 码申请入口(登录后在 Profile & settings 申请):https://www.giffgaff.com/auth/login
▸ giffgaff WiFi Calling 官方说明:https://help.giffgaff.com/en/articles/258841-understanding-wifi-calling-and-volte
▸ giffgaff 余额退款人工客服入口:https://support2.giffgaff.com/app/ask