Years ago, long before Facebook etc., I had a quilt top stolen from a shop in Texas where I was teaching. I made all kinds of squawk about it to every person, every shop, every guild in the area I could find. One day not too much later, the quilt showed up in a plain wrapper in my mailbox, no return address, but postmarked near by. We never learned where it had traveled.
But, all I can say is, I'm glad you are making contact with as many quilters as you can, because that is likely the only way to get them back. So very sorry this has happened to your shop.
Jan in VA+