They had up to four years to sue you for civil fraud. After that the Statute of Limitations ran. Highly unlikely a proscutor would bring charges after six years even if they could, but they likely can't because the Statute for filing a charge for criminal fraud is limited - - see below . . . but see the exception. Note if the lawyer is threatening you with criminal prosecution if you don't pay the bill, he is in violation of Florida Bar ethical guidelines. They won't sue for such a small amount and even if they did you can deny the claim based on the Statute of Limitations. But on moral grounds you may want to consider paying the debt. That's probably the right thing to do and you will hopefully sleep better at night.
775.15 Time limitations; general time limitations; exceptions. —
(2) Except as otherwise provided in this section, prosecutions for other
offenses are subject to the following periods of limitation:
(a) A prosecution for a felony of the first degree must be commenced
within 4 years after it is committed.
(b) A prosecution for any other felony must be commenced within 3 years
after it is committed.
(c) A prosecution for a misdemeanor of the first degree must be commenced
within 2 years after it is committed.
(d) A prosecution for a misdemeanor of the second degree or a noncriminal
violation must be commenced within 1 year after it is committed.
. . . . . (5) The period of limitation does not run during any time when the
defendant is continuously absent from the state or has no reasonably
ascertainable place of abode or work within the state. This provision shall
not extend the period of limitation otherwise applicable by more than 3
years, but shall not be construed to limit the prosecution of a defendant
who has been timely charged by indictment or information or other charging
document and who has not been arrested due to his or her absence from this
state or has not been extradited for prosecution from another state.
I agree with the statement of limitations by the other attorney, but there is a potential tolling (stopping) of the clock when fraud is alleged. The statute of limitations allows for the statute to begin running when the victim knew or should have known that the fraud was committed.
Call a qualified criminal attorney in your area.