i started a project putting in some parking lot lights. I am an electrical contractor. i casually asked the manager and person that hired me when i was going to get paid after finishing the project. he said 30 days to which i said i am used to getting paid immediately at completion of the project. how can i make sure they pay me quickly? Can i tell them they need to pay me right now for materials delivered to the job? can i hold the job hostage until they pay?