The irs claims i was paid 10k from a group settlement now i have to call the company that reported it HELP!!!?

I just recieved a notice from the IRS claiming that i was paid 10,000 from a lawsuit against guitar center whom i worked for in 2005 (this was on my 2006 year) but i never recieved any payment and heard very little about the lawsuit now i have to call rust consulting out of minneapolis who handled the settlement and also reported the claims. the irs wants $915 or proof that this is a clerical error from the company. so now its 2008 am i still entitled to this money since it was reported to the irs? if this company trys to dodge me do i have any defense against it can i tell the irs they wont cooperate? will the irs have my back if they wont? will my bank records from 2006-2008 be sufficient proof i never got this money? if they dont pay me am i still on the hook for the taxes owed on it. ive heard rust consulting can be nasty to deal with i just want the cash or to nothave to pay taxes on it if i dont get it but if they reportedit are they obligated to pay me now that im being audited