A Senator or Representative is a good option but there are three faster and better options:
1. Formal Letter Inquiry by an attorney
2. USCIS Ombudsman in Washington, D.C.
3. AILA Liason inquiry
Feel free to give me a call if you'd like to discuss this further.
Attorney at Law
Disclaimer: This answer does not create an attorney-client relationship and is for informational purposes only. It is not, nor is it intended to be, legal advice. You should consult your attorney for legal advice tailored to your individual circumstances.
One suggestion would be to contact your local US Senator or Representative's office and see if a staffer would be willing to contact the USCIS on your behalf. He/she may be able to find out what is going on and how much more of a wait there will be. I hope that this is helpful to you.