I’m a subcontractor working on a commercial project which was recently finished. Our first progress payment was due 12/17 and sent on 12/29. Our final payment was approved by their Project Manager today, and we were told payment would be sent tomorrow. However, their accounting team is saying they will not release our final payment because they have been contacted by a third party who claims to not have received payment from us. We did not list any other subcontractors on our written agreement with this company, and all work was performed by our own contractors. We have expressed that we cannot pay for labor until we receive payment, but our customer is still refusing to withhold final payment so they can investigate what needs to be done. Should we send a demand for payment or lien notice to the property owners?