I don't think he'll read your comment. In fact, it might be considered calling out, so you may be better off deleting it. If you want to talk to the winner about this then maybe do it directly (you have his steam account and his email address). Then again, you might be better off not involving yourself with him any further.

I recommend requesting a reroll and waiting to hear back from support before you give anything away. I'd say that a reroll is justified because, while chasing down the winner to demand the prize before 7 days is against the site's guidelines, creating fake trade feedback in order to do so is outright abusive, so you might have a shot. Either way, at this point it's fair that the winner waits until you have heard back from support before receiving anything. Open a support ticket; Category: Request New Winner | Reason: Suspended or Inappropriate Behaviour, and hope for the best.