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I can only imagine how upsetting this situation must have been. Unfortunately, though, it's not one for which the law would typically provide any recourse. For one, you resigned and in general you cannot collect damages arising from the voluntary decision to stop working. But even if this were not the case, the underlying situation about which you complained was not a protected activity. In order for the complaint to come under the whistle blower statutes, you typically would have needed to complain about something illegal and you would have needed to make your complaint to a government entity (i.e. reporting tax fraud to the IRS).
While perhaps unethical, it is not illegal to be selective in terms of who a manager chooses to bring to a survey. This is purely a matter of internal company politics. So, complaining about this sort of thing does not confer any sort of special legal protection. While highly unfortunate that HR would lie to you about your complaint being anonymous, that representation does not amount to a binding legal contract. Again, it comes down to company politics. It's highly unfortunate, but sometimes these sorts of betrayals happen, and the law does not get involved or offer protection.
So, I am truly sorry to say that this is not a situation for which you would typically have any recourse under the law. I can understand why you left this job, and I truly wish you the best in finding new employment.
I hope that you find this information helpful. Please do not hesitate to let me know if you have any questions or concerns regarding the above and I will be more than happy to assist you further.