I typed out a response to this, but then deleted it because it was borderline inappropriate.
I'm sorry that the people that stocked your pond ruined it.
I read stories like this all the time.
When is someone going to stand up and make these people pay for the trouble that they cause?
I have been screwed over enough in my life. When someone does you wrong, and they did you wrong by putting bluegill in your pond, they should be held liable.