I know this isn't the answer you're looking for, but one thing you can do is let some time pass before clicking next game. That way your previous opponent will likely have been paired already.
No means no!
Well, I can solve it by blocking my previous opponent too, which I have taken to doing because of this stupid functionality. Then I unblock them again, if I remember, once I've been paired with someone else.
I only play Crazyhouse in my lunch time break at work so I don't exactly have time to wait 5 minutes in the hope my opponent has a new game. I don't mind the wait for a new opponent if it's someone different though. If it takes too long I'll just give up or play regular Blitz instead.
Wow, does it take 5 minutes to pair in crazyhouse?
In blitz I have to wait a few seconds. So to be sure my opponent is paired I'd just wait a few seconds (and if they didn't click new game right away then I'd have to be really unlucky to be paired with them again)
It doesn't take 5 minutes, but it can take a minute or two, so obviously more if you are waiting to be sure. I mean I don't care if I occasionally get paired with the same person again, it just happens > 50% of the time, which is not sensible.
Looking at the title I thought this thread was going to be about a completely different subject.
yeah, semantics

I've complained about this before, both directly and in the forum without even getting a response from chess.com saying 'We don't care what you think', which would at least be an acknowledgement!
Why do I keep getting paired again against the person I just rejected a rematch from in Crazyhouse? I know there aren't so many players so I'd have to wait longer for a game, but seriously? How hard is it to understand and implement that No means no? If I wanted a rematch I'd accept one. When I click 'New' and reject a rematch I'm clearly saying 'pair me with a new random opponent'. But no, time after time I get paired with the same person. You might as well just put the tick button on the rematch dialog and not allow people to say No.
And it's nothing to do with whether I win or lose. I reject all rematch requests, whether it's an easy win, hard win, close defeat or clear defeat. It's my choice that I'm allowed to make. Or at least I thought it was.