Landlord won't allow me to use my last months rent deposit towards last months rent! Is this legal?

I live in Marion County Florida. When I rented my home in July of 2010 I signed a1 year lease. I gave the landlord (real estate property manager) First and last month's rent ($1350 each) plus one month Security Deposit ($1350) plus a $250 non refundable pet deposit. I just notified them that we will not be renewing our lease and he told me I can not use my last months rent (that I gave when I signed the lease) to pay July's rent. That they hold the last months rent until after we move out. I have to pay July's rent and after inspection of the home I would receive both last months rent and deposit back (if everything checked out ok). This doesnt seem right to me. We just bought a home and don't want to have to pay two rent/mortgage payments in July. He said if I don't pay July's rent he will process an eviction on July 3rd! Is this legal? Thank you.