Maybe they have a process when disputes like this happens. 

You can dispute if you feel that the amount is too low, however this delays the lease signing as a supervisor must review.For reference I have two fully renovated 3 bedroom properties in C- areas in the city with rents of $1351 and $1301.

Glad to know you were able to talk it out and come to some resolution with your tenants.

However, I've found quite a few disputes in regards to it that were decided in favor of the potential tenant.

They have to dispute it with the credit agency or via court if they don't agree.

It just means had you stayed, you could have disputed the $75 - not completely avoid paying a whole months rent. 

I would try and dispute it with your bank to start.

Cops in Florida won't do anything about it, maybe they'll file a police report but usually this will simply be filed under landlord tenant dispute and you'll be told it's civil. $650?

Next time I would charge them a pet fee instead of a deposit, if their dog destroys something you'll have to go through the deposit claim process which they could (and often do) dispute.  

@Seth MacomberNo doubt a resolution has relieved some stress and hopefully the family can move forward.