month to month tenancy question in Florida

[Carrie Jel]

my renter gave notice on Jan 22nd that he would be buying a house and closing on March 11th.  We agreed he would stay until March 15th.  I prorated the last months rent for the last 15 days in March.  He moved out early today giving me 5 days notice of him leaving Feb 27th.  .  I do not have a new tenant as of yet but I think it will rerent around april 1.  There will probably be a lapse of 2 weeks.  

  I attempted to show the property and he would not allow me to do it.  Finally he left and very hostile I may add.  I do plan on returning his security deposit.  However he told me he was closing earlier and leaving earlier.. the house is not rerented.  Do I need to return the last 15 days?  Or can I legally keep it.  I am reading my lease tomorrow to see what it says.  I am a total amatuer.. I have never had this type of situation before.  I would be glad to refund if I had a renter sooner but they blocked me from entering the property without excessive drama.. this is besides the point.  Do I return the 15 days?  I am returning the deposit despite a few torn screens.  I am not sure if that wouldnt fall under wear and tear and it is not expensive to return.  

The tenant could take me to small claims.. please give me your imput.  Thanks