Check your spam filter. You may need to log into your email provider's web site and check there, in some cases they may be doing some kind of spamblocking that could prevent you from ever having seen a message. If you've emailed
ticketsupport@burningman.com and gotten zero response back that's almost certainly the case, as there's an automatic acknowledgement email that's sent to your address almost immediately after you send them an email. While logged into your provider, you may want to add
*@burningman.com and
*@inticketing.com to your trusted senders list (or add a filter to never send messages from those addresses to spam).