Never mind how to sell it.
The big question is who's going to buy a failing business whose product supply is drying up?
You might get a dime on the dollar for your furnishings and equipment and maybe a few bucks for your leasehold interest if you have favorable terms and someone wants to take over the lease and use your area for his own business. Keeping in mind that the LL will continue to hold you responsible for the lease for the next 5 years no matter who is in the place.
You might want to consider bankruptcy and pull the plug now, rather than continue to hemorrhage money and be stuck with a long lease.
Or find another supplier and keep plugging away at it.