To contact the FAA you have two choices:
1 – Fill out the FAA Hotline Reporting Form on the FAA website at:
Note: This is the Washington DC FAA office and they report directly to Congress. Before you hit send, print a copy and send it to your local representatives office, most likely either Jackie Speier or Anna Eshoo. The Washington DC FAA dept is overseen by Congress. They are the very top of the food chain.
2 – Download the sample letter (docx format) and mail to the address on the letterhead.