If there is such a thing as a good side, it would be that you learned about it now not
in March. After doing weddings for three daughters and observing their involvement in probably dozens more, this does not surprise me. It just happened to a wedding party my youngest daughter was involved in.
First thing to do obviously is to find a reputable company to reorder dresses through.
It is also remotely possible that the manufacturer was paid for the dresses and might deliver them directly to you or to another shop.
Any possibility that the girls paid with credit cards? If so the charges should be immediately disputed in writing.
Also check your local laws, the new person taking over the shop may claim no responsibility but in fact may be responsible.