Is he having a tough time at school or something similar? Obviously I don't know your kids but if one of mine had a strop about something like this I'd think there was something else going on, especially at 14.
Keep the XBOX - but don't set it up and don't let him either.
If he really wants it, which I imagine he did if you were willing to spend so much money on it, then I wouldn't send it back just yet. I agree with posters that consoles are very important to kids. My DS loves his XBOX and is always playing on it with DD2. DD1 doesn't like the XBOX as much as the others but they all play together on the WiiU quite frequently, and I value that because it's not often they'll all play together (especially with the age gaps). But perhaps more relevant to you, my DS is the same age as yours and the XBOX is essentially how he keeps in touch with his schoolfriends. I think games consoles (and the bloody Fortnite game) are quickly becoming pretty integral to social lives.
That said, wait a while. If one of my DC did this I know they'd apologise as soon as they'd realised how awful they'd been. If he comes down and shows some remorse I'd not return it but there'd be a waiting period before he can actually use it due to his behaviour.
If he thinks it's acceptable, in which case he is very entitled, I'd return it. Get him a new book series- the Gone Series, Percy Jackson (though I warn you, there are about twenty books total so if you start and he gets hooked on them, which IME kids do, that's the end) or Harry Potters if he hasn't read them. And maybe a board game. My kids love playing Monopoly together.