Hello and welcome to JustAnswer. Please note: This is general information for educational purposes only and is not legal advice. No specific course of action is proposed herein, and no attorney-client relationship or privilege is formed by speaking to an expert on this site. By continuing, you confirm that you understand and agree to these terms.
I am sorry to hear about this situation. I am not sure why, but your question only came up now. Likely if you had originally asked this question in the UK Legal Category, it was (rightfully) re-categorized to the US Legal category. That may explain the wait as the re-categorization can take a bit of time.
Anyhow, if someone in your situation wants to report a fraudulent immigration case/matter to relevant US authorities, then that person has the following options:
1) Call U.S. Immigration and Customs Enforcement at 866-DHS-2-ICE to report it as a tip; or
2) Report this online HERE and click "Benefit/Fraud Marriage" as the option on the form.
I hope this helps and clarifies. Please use the SEND or REPLY button to keep chatting, or please RATE when finished. You may always ask follow ups at no charge after rating. Kindly rate my answer as one of TOP THREE FACES/STARS and then SUBMIT, as this is how experts get credit for our time. Rating my answer the bottom two faces/stars (or failing to submit the rating) does not give me credit and reflects poorly on me, even if my answer is correct. I work very hard to formulate an informative and honest answer for you; please reciprocate my good faith with a positive rating.