I merged my business with a friend of mine and have a past due balance with a general contractor. We recently engaged on a new project with this general and was told to bill him for the current and past due invoices. So, we worked for a few weeks and have billed all work performed and past due invoices and have not been paid. When preparing my paperwork to use legal services, can I include the previous past due invoices? They did tell us to bill them through this project?