Opinions?

I know a Great Dane breeder who had a previous buyer return one of the Danes she bought a year ago because they realized having two in the house was too much to handle. Plus the brother is much bigger and bullies the female who they are sending back. The breeder used to work with me and contacted me knowing I've owned Danes and have been wanting one in the near future. The pup is supposedly very sweet and I made the mistake of telling my ten year old son we might get her this weekend. The breeder though has contacted me saying the dog arrived today and she's so sweet she may want to keep her herself now. I'm sorry but when she contacted me it was with the intention of rehoming the pup not just with wanting to discuss the possibility. We set up dates to meet her and as long as she isn't aggressive like the previous owners said she's not then we could have her. Now I know she can pretty much do what she wants but does anyone else see this as rude in anyway? I could tell my son unfortunately it just didn't work out because i wouldn't tell him sorry the breeder changed her mind and is going to keep her as a pet for herself now. Am I over reacting? Just pisses me off a little and seemed unprofessional to basically make a deal and set it up them say nevermind I want her instead.