home owner won't pay

WE are under contract to build a swimming pool. We are at the third draw and all work is done according to contract. The homeowner refuses to pay this draw until the pool is complete. According to the contract this draw is due now and another draw due at job completion. We have placed a lien and have recieved a letter from him stating he is going to hire a new contractor if we do not continue work within 72 hours. A letter and copy of lien were sent by certified mail which he has not yet signed for. We want it foreclose on the lien, but are unsure of the next step. Any lawyers around Hernando county Florida for hire please let us know. FYI it has only been 2 months since we received the permit and one week away from completion. Thank you