I've personally never received a response on any support tickets from Poloniex, so I wouldn't be surprised if the ticket goes unanswered for days. That said, the system is pretty good at resolving conflict issues like this by itself. Typically it will either process a few hours later, or cancel the transaction and recredit your account. If after 48hrs it's still not resolved and support hasn't responded, I'd try calling them (phone number is on the site footer).