Why is my phone completely unresponsive?!

I was texting on my ZTE Blade Z Max, and it froze. Completely, volume and all. The touch screen won't work at all. (Mind you, it's not cracked at all.) And even when I plug it up to charge, it doesn't make a peep. Does vibrate, I don't even get notifications. And would ty and power it off, but my power buttons EXTREMELY tedious, not to mention I can't even see if the menu thingy would come up because it's frozen. I need help. FAST.