My first suggestion would be to follow Z's advice as we get many reports of this happening and the most frequent issues are email ending up in your spam folder or the transaction not actually being completed.
As for their contact information here you go:
The Elio Motors direct customer service support system email address is:
support@eliomotors.zendesk.com
You can also reach them by phone:
Phone Hours: M-F 9am – 3pm Central Time
Toll Free: 1-844-BuyElio (1-844-289-3546)
Direct: (480) 500-6800
http://www.eliomotors.com/contact/