You might want to send them a registered letter, return receipt/proof of delivery required, demanding immediate communication and/or return of deposit. Better yet if you can have a local attorney send it.
If there is no response within 3 days of said delivery you may be dealing with theft of funds and/or fraud for putting you off. At that point the local NC District Attorney's office might be the peeps to call.
BTW: As you are dealing with an interstate commerce transaction, there may also be some federal issues here as well.
All that said, I hope you can stand the loss, it doesn't sound good.
BTW: Recent events have suggested that some complaints sent to BBB's may never see the light
off day, especially if they are not a local BBB dues paying member. "No Complaints" is not always good news.
From the BBB Site:
This Business is not BBB Accredited
(800) 418-2120106 Railroad Ave, Suite G, Gibsonville, NC 27249