So, that is good that the breeder was inexperienced, she probably just doesn't know how to sex properly, or got confused. We have every reason to believe they will be a great breeder, but just need some more info and experience.
I would reach out the them to let them know. My friend down the road that breeds will trade out roosters, since she knows she isn't good at sexing either. She has to quarantine birds since they have been with another flock, and some breeders won't trade out because of this. The breeder should at least give you something back if they sold these to you as "pullets".
I have had great luck finding new homes for roosters and craigslist and the neighborhood forum. I have even had people pay for them when they are pure bred, and those look pure BR to me, so someone may want those genetics for their flock. Demand on roosters will vary depending upon where you live. Are you rural or urban?