I tried to sign up with Poloniex and they said a confirmation email would be sent within minutes.
It's been hours and I haven't received anything. I've checked spam folders - nothing. There's no
way I can ask their support unless I'm signed in which I can't. Any suggestions?
It could be because they don't support the email provider you are using? I'm not sure what you are using but try to switch to something else that is commonly used. (Yahoo, Outlook, Gmail etc.)