I don't see an answer to what happens if the tenant vacates the property unexpectedly and causes thousands of dollars damage/lost rent to landlord?

The answer depends on a few factors, the most important of which comes down to the lease, the management contract with the property management company, and the date the tenants moved out.  With regard to the tenant, the Florida statutes dictate what to do and how to do it and it depends on how they moved out and when they moved out.  That part has to do with applying the security deposit to the damages.  From there, you would look to sue for the remaining.  The dollar amount dictates which court you would be in – under 5k, small claims; 5k – 15k, County Court; and over 15k, Circuit Court.  Depending on what the management contract (and perhaps the lease itself) says, you may be able to hold the management company liable.  I’d make an appointment with a litigation attorney sooner rather than later.  This forum is a little complicated to discuss all of the ins and outs of a possible suit, but, on these facts, looks like your answer is going to be in the courts.