legal representation

bs'd I am an inventor and got myself involved with a bad company called invent-tech. They sent me an NDA which lawyers have told me "do not hold water." Before I knew this I paid them 900$ to do an evaluation which had a garuntee and it was basically worthless. I need someone to evaluate the NDA they sent me and if you find it inappropriate to write a letter to this company stating that, then requesting a refund for 900$. Thank you and good luck bidding.