My solution is a little different. :) I have lost money too and have been cheated many times. But i simply ignored it all and continued with my life and mostly i tend to blame myself. I reasoned out to myself that such thoughts makes a person negative. All these thoughts about suing, revenge, etc are negative energy and it tends to destroy your inner peace and your thoughts tend to become violent. You get depressed, you loose sleep, you get headaches. So i developed a simple solution. To let go. 

I know some of you might get angry and call me a coward or something but this is the person i have become. I am happy. This solution is not for everyone but for those who can do this, they will find inner peace. You might think i am rich but it is not so. I was a poor guy when i started to behave like this. If you have enough on your plate, it is best to let go.