I agree with championny. They cannot make you pay for them. It was their mistake, not yours.
My sister order some chuckers (?) from Cackle and it took forever for her to receive them. When she finally did, then they were all dead. She contacted Cackle and they said that they would make things right by letting her either order some more birds or credit her account or whatever she wanted to do. Every time that she wanted more birds (chicks, this time), then they were out of those or she couldn't get in touch with them at all. That has been over a year ago now and she finally just took the loss and never ordered from them again.
Dorothy