HOW TO GET A COMPANY TO PAY YOU FOR THE WORK DID FOR THEM ?

If you have the records of how much you were entitled to get and how much you got, that's good enough. Why they withheld it completely another matter. With good faith in them to buy equipment later on, you let 50% of your earnings be with them. Does this have any agreement that you are giving 50% of your income for future buying. Any way just secure all the records, go to a lawyer and make them get a notice. Your money should come running your way. Else go to court and they will pay 100 times more for the money and the mental harassment done to you.