Repaying relocation expenses, should I hire an attorney?

About 6 months ago I accepted a new job and moved my family across the country. On my first day, my job was changed (title remains the same) and I was put over a different division without the 6 person team that I was told I would have. The initial job description seems to have not ever been truthful as a longtime employee has the position that I was told I would have. None of this is outlined in the offer letter. One other relevant point may also be that the company has merged and changed names during these past 6mths. My offer letter says that I am employed by the original company, not the new conglomerate.

I would like to quit. Does this situation leave any negotiating room for relocation payback? My offer letter states that I must pay back my full signing bonus and relo costs if I leave within 2 years. Is it worth hiring an attorney to try to reduce the amount? How do taxes work in this situation? Thanks for your help.