Gov Contractor not getting paid.

My husband is a contrctor for Army Corps of Engineers. He has had this postions for over 5 years. The contract has changed compaines 3 times. The last time the contract changed companies there was a pay decrease. However per the Contract they must be paid a min. amount. The "New" company took over in May of 08. In November 08 they announced that they would be paying their contractors back pay because they had made an error equal to $1.00 per hour worked. They said they would calculate all hours worked from June 1 08 until "Today" and pay the back pay. That never happened. In Dec. they stated they were forming a commity to decided how to handle issuing the back pay. An announcement that the pay would would paid on the last pay check in Feb 09 was made. There was no back pay issued, however they have ajusted the paytroll to reflect the additional $1.00 per hour. At first it was just a few hundred dollars but now it is several thousand that they owe us.

What are our rights? Is there a time frame in which they much pay? Its not just us it affect a few hundred employees. They are not denying they owe us the money they just dont pay it. They came to us and said hey we messed up and we are going to pay you. We are in Minnesota.