All I can say about filing a lawsuit on the same day as the trustee sale is, it's too late. I know here in Washington State, you have to file them within a certain timeline. I forget what it is without looking it up again. But if you don't do it within their prescribed timeline, you wave it and there is nothing you can do about it after that time. I suspect that is what has happened with you.
At this point, I think your only option is to prove wrongful foreclosure by showing they didn't own the note, forged documents (robo-signed)or something showing they defrauded the court causing it to wrongfully foreclose.
Just my 2 cents worth.