CostPCO

Hi, hope to get some assistance on a tricky issue here! I have a contractor on a CPAF contract that has been performing a changed condition under a UCA for several months. The definitization proposal just came in, without any incurred costs included. When I questioned the contractor on its incurred cost portion of the proposal, the contractor admitted that it has not segregated and accumulated costs for this UCA. I am left in a quandry - how can I definitize the UCA without receiving incurred costs as a part of the propsal?