Problem M8 OTT 4K Tv box reset button not working

hi guys, I was able to reset my box using the reset button on the back of the box fine earlier, I done a factory reset, and then done a reboot. It got stuck on the MBOX logo, so I left it for nearly an hour, just the same. So I tried to reset it again, using the same technique, with the reset buttom. But it doesnt work anymore. I hold the reset button and then pout the power cable in while still pushing the button in, but it just goes straight to the MBIOX logo, and nothing happens again. Any ideas?

Thanks