We are a sub-contractor and multiple invoices are used for 1 project. We sent a NOI to a General Contractor regarding a project, for a specific invoice, and they paid in full. So that has been taken care of. However, the GC has sent us a back charge on that specific job as a whole. The back charge is not for any specific invoice. My question is what is our lien rights in a situation such as this? How do we move forward with a NOI/lien for that?