I get the 360 guide freezing from time to time on my formerly V6 boxes. I don't understand why. It unfreezes itself after ten or twenty seconds. It's annoying but not a disaster. Hopefully, a software update will fix it one of these days.
I can't comment on your other issue. It's never happened with either of my boxes.
Thanks for your recent post and welcome to the forums! I'm so sorry to hear of the issues you've had with your 360 services recently.
I've been able to locate your account using your forums details and can see that you've been able to speak with the faults team in the meantime who have arranged a replacement box for you following some checks.