I am a prime contractor and have completed 85% of my obligations according to the contractual agreement I signed. Now my client refuses to release funds I was supposed to receive one month ago. I need this money to complete the remaining 15% of project I am still obliged to complete. He claims that I've taken longer than agreed, but that is incorrect and I am still within permitted time according to our contract. I've paid labor and materials for 25 days prior to this and am being hindered in my ability to complete my obligations by his actions. What would be advisable for me to do in this situation? Thank you for your valued advise.