I'm feeling so sad now too! It's incredible how careless people can be when it comes to animals. I hope you're getting your bunny back and maybe someone else will come and give her the bun a nice new home.

In Germany cats and dogs are given away with a 'Tierschuetzvertrag', a contract you have to sign in which you agree to properly taking care of your pet and that the breeder/former owner has the right to come and visit in order to see if the pet is taken care of well.

I'll keep my fingers crossed that the mother has a good heart and brings the bunny back to you.