You know your employer is violating the law. Perhaps, he has benched you with no pay; is paying you less than the required wage; has you sending out resumes instead of writing a computer program.
So why do H-1B employees put up with this situation?
One of the main reasons an H-1B employee tolerates exploitation rather than filing a complaint against the employer is fear of being deported.
This fear is understandable, but protections do exist. Specifically, regulations prohibit the employer from threatening you and retaliating against you if you complain about his violations of the law. 20 CFR 655.801.
Read the full article on the blog H1BLegalRights.com.
WI Employee Rights Lawyer: Severance, Wages, Job Termination, Discrimination 
I filed a WH-4 complaint and then I told my employer about a complaint. Now they are terminating my employment. How is it possible for them to do so if there is a law? Are there any loop holes for them to prove it is not a retaliation.
I am sorry to hear your job was terminated. From the general information you describe, there may be strong grounds (and strong proof) for a retaliation claim. However, I could not provide you legal advice without communicating directly with you and evaluating the full situation (e.g. learn more about what the documents, witnesses and other sources of evidence indicate).
You could contact an attorney for further assistance, and someone at DOL may be able to tell you (whether you have an attorney or not) how to file a new or amended WH-4 complaint that adds a retaliation claim. If you want to have an attorney evaluate your matter or take action, you should look into this promptly, as legal deadlines apply to any potential legal claim for retaliation.
Unfortunately, the existence of anti-retaliation laws often do not alone stop an employer from retaliating, just like the presence of a stop sign does not make all drivers stop their cars. Some will ignore or disregard the rules.
I wish you the best, and am sorry again to hear of your job loss.