Regarding Contract and payments

Hello Sir/Madam, Myself Thulasidhar. S running Proprietor company Allianz Enterprise in Anekal, Bengaluru. Problem going to explain below We worked for (D company Pvt Ltd, Bengaluru) in August 2018 in Hyderabad which they have taken contract from (C Company Pvt Ltd, Bengaluru) where C Company taken contract from ( B Company Pvt Ltd, MNC Global company ) where B Company Pvt Ltd taken contract from ( A Company Ltd. All India) A company Ltd is main client. We have executed electrical works of A Company Ltd office works which is located in Hyderabad. D Company couldn't complete works taken over by them at that stage C company Pvt Ltd referred us to D Company to carry over works. We & D Company agreed for some prices to complete work based on Quantity. Some of the works we done; Wires laying Lights fixing wiring for Work stations etc etc Here please consider this point as important Assume we laid wires from Point 1 to Point 2 is 100 meters we billed D company Pvt Ltd for the same 100 meters, but D company not agreeing to pay us for 100 meters but they are telling its 80 meters only, but D Company Pvt Ltd is charging C Company Pvt Ltd for more than a 100 meters. We don't know how much C company Pvt Ltd charged to B company Pvt Ltd and B company Charged to A company Ltd. Here main point is who ever works distance will be same from Point 1 to Point 2. So D company is not ready to pay us for what we worked. Its almost 1 year, we have cleared payments to all our labors by arranging amount from outside . Now i am in trouble i have to clear my credits. We regularly following up D Company Pvt Ltd to clear our bills but still not paid. Up to my knowledge C Company Pvt Ltd cleared payments to D Company Pvt Ltd. Sir, I need legal advise for this case, how i can proceed further to get payment for what we worked. Please contact me for any clarifications Thanking You With Regards Thulasidhar S