We sold material for a job to two separate customer's. The first customer we last shipped material on 3/26/19 and was fired from the job by the builder. The second customer took on the job & we last shipped on 6/26/19 and we have another $41K in open orders. The first customer said the builder is not paying them & so we are not being paid. The second customer seems to be paying. We want to salvage the relationship with the second customer but we are concerned with getting paid for all invoices. Your advice would be appreciated.