Five years for a written contract, four years for an oral contract.
You must find the person so they can be personally / individually served
by the process server.
Did the tenant provide you with a forwarding address? I presume so since you state that the tenant is ignoring you. Your next course of action would be to file suit against the tenant in small claims court. If the tenant has moved out of the state of Florida, that won't be a problem. Just find out what county they now reside in (whether it's in Florida or another state) and get the former tenant served after you file the complaint. The clerk will automatically set the matter for a Pretrial Conference. If the tenant fails to show, the judge will give you a default judgment and then you have the fun of collecting on the judgment. Getting the judgment will most likely be the easy part. Collecting on the judgment might require you to seek the assistance of an attorney.