File a complaint with the BBB and dispute the charge with your bank or credit card company.

This Message was on their site this morning-
""In cooperation with the CPSC (United States Consumer Product Safety Commission), Hoverboarder.com will be ceasing all operations, and as recommended by the agency, we will no longer be shipping any of our hoverboards.
IF YOU PLACED AN ORDER THAT WAS NOT RECEIVED YOU WILL NEED TO CONTACT YOUR CREDIT CARD COMPANY TO REQUEST A REFUND.
Instructions To Obtain a Refund:
1) Contact your cre- See more at: https://hoverboarder.com/#sthash.4L2NoXJ6.dpufdit card provider by calling the phone number on the back of the card.
2) Inform them that you would like to dispute a charge from Hoverboarder.com
3) Provide them with any relevant information regarding the transaction.
If you need any further instructions, please call us at 866-981-2737, Monday-Friday 10am-5pm.""