We did time and material work for Brantley Construction. They issued us a po based on time and material but not a specific dollar amount. We sent a total of 5 payment apps with the last one being on 11/12/21. We were paid for the first three apps. There has never been any contact about any problems with the work or the billings. I am getting excuses every time I actually hear back from them. The last time was on May 11th when I was promised that payment would go out that week. What can we do to collect this $20,510? Thanks.