The burden of PROOF, is on you. So, that means meticulous work on your part.
You must present yourself concisely, and clearly and have FACTS to present.
Nothing short of Facts will garner any support, anywhere.
I emphasize, FACTS, not suspicions, not rumor, nothing but cold hard FACTS, gathered over a sufficient sample size to be significant.
Also, explaining the nature of how you were cheated will help. In the OP you only state you were cheated. I got cheated out of some sales tax money today, and I could actually prove it, but whether or not it is worth my time is another question.
So think long and hard about this, and KNOW deep in your heart that this is a crusade you are willing to make. Then start gathering FACTS.