I received a Raspberry Pi 3 at the excellent PiCademy I attended in May last year. However, it now doesn't respond to any USB devices, despite me trying different power supplies, different SD cards and different USB devices. It doesn't seem to be giving any power out, so keyboard lights, WiFi dongle lights etc don't light up when they are plugged in. They do light up when I plug them into a different Raspberry Pi.
My question is about warranty on these devices. Does anyone know how to return them to the manufacturer, as obviously I don't have proof of purchase, or even know where they were purchased from?