RODE Podcaster microphone doesn't pick up my voice?

I have tried it on both iMac and Macbook Pro and i'm starting to think the microphone is just faulty. The computers recognise that it is connected (via USB) because I can select it under system preferences > sound etc, but when I try to use it, it doesn't pick up my voice. I have tried selecting it in Garageband and selecting it as a default in there, it recognises it within the Audio MIDI Set-up, tried turning the volumes all the way up just incase it is quiet but I'm still having no luck.

Its a brand new RODE Microphone bought from Amazon so there can't be any issues surrounding drivers as it comes with the firmware.

Any ideas would be gratefully appreciated!