Moto G Not Working - Less Than an Hour's Usage?

So I got my mum a Moto G and it looked great. I booted it up and set it up for her, and it appears I may have forgotten to switch it off, so the battery drained. With most devices this generally isn't much of a problem. When I came to charge it (using my Nexus 4 charger because no charger was supplied), the notification light came on briefly as if to indicate that it was charging. I tried booting it up... To no avail. I tried again half an hour later and it still refused to boot up. I've tried booting it into recovery mode, no such luck. It's been charging for about two hours now and I've tried quite a few times to get it to boot up.

Has anyone else had similar problems? If so, how did you solve it, or did you just have to send it back? I'd rather not have to send it back - it would be a fair bit of hassle and it's not looking brilliant right now for a phone which has received critical acclaim. Oh, and I've tried multiple chargers and cables, none of which seem to have worked thus far.

Thanks!