Min wages

I am officer incharge for a Company owned Company operated Retail outlet(Petrol Bunk). The daily operations in bunk would be taken care by a contractor(agreement for 3 years). The cost incurred in providing manpower will be reimbursed by our company. But he has to pay wages to people deployed as per minimum wages in the respective state. as per agreement. The contract run by a contractor upto 31-08-2014 and contractor was changed on 01-09-2014. But previous contractor used to pay Rs 30 per day per employee ( Average employees 30)more than min wages. So this contractor also followed the same and I want to reduce to this wages to actuals. Though I advised the present contractor orally to submit bills as per min wages he is not following. I also cannot point out this issue in writ now, as I has been passing bills for 9 months if so our company can recover from me. Whether I can recover the whole amount from starting of contract or reduce the bill amount to actuals though contractor will be submitting for excess wages.