Words of caution: I may be wrong, but you gotta listen everybody in America and decide on your own, so here I go.

As per my understanding, H1B visa requires that you do not displace any American's porspects to get that job, (after all it is their country, not ours!! America knows how to secure the space for its people from all immigrants, all types of aliens whatever!) This visa also means that you are getting the same pay as any American would have gotten if he/she were hired in that post. So I believe, when your employer filed the petition for this visa on your behalf, it must have proved to USCIS that you are getting paid the understood rate or payscale. (Do you have the copies of H1B papers filed at that time?)  I cannot understand how your employer can deny from what it has already promised to USCIS for you. I think it is not you, but your darn employer who can get in trouble, if USCIS is let known about this mess, since your company has lied, which is like basically comitting a crime especially in this country.
As is known, there are always this bunch of people especially Indian shits who are trying to find loopholes to abuse the system and take advantage of people like us.
I would be stumped, if you tell me it is an American company!!