Adjustment of Status - I-485

My husband is an American citizen and he sponsored my I-485 in Sep 2017. We chose Seattle as the field office. Now the processing time for family based I-485 is in Dec 2017, but I still haven't got my interview scheduled. I submitted an inquiry in a congresswoman's office, and it turned out that my case is still stuck in Texas process center, and stuck in the queue of employment based. I went to a senator's officer today, the case worker there pretty much said USCIS can process cases whichever they want. My old employer submitted an I-140 case for me, but I left them before I-140 got approved. They never withdrew that I-140.

I have submitted service requests to USCIS to correct their mistake. However, apparently they never did.

I'm really very upset and don't know what to do, when they just refuse to correct this huge mistake. I want to ask what should I do in this case? If I hire a lawyer, what can a lawyer do?

Thank you!