Florida. Received 3 day notice and letter on the door specifying amount due including legal fees. We took the full amount to the office. Now, LL says she won't accept our payment unless we pay next month's rent also. Can she do that?
The 3 day notice is most likely invalid if it had current legal fees included. Old payment might have been used for legal fees and late fees first if this was included in the lease. However, this is not okay for current fees. If you paid the rent you are okay.
However, that only handles the notice, fees might still be due.
What kind of lease do you have?
The LL might give you a new notice if you don't pay the next rent on time (and keep in mind that late fees and legal fees might be paid first before the rent).