Glad you did not lose you cool! Don’t give up your fish, this only teaches them sharks and groupers that divers have a free meal for them! Don’t attach your fish stringer to you . Also it is the law to stay away from divers with thier dive flag up, I know a guy who lost his legs and almost his life to a boat prop! Next time if you can get the FL numbers call the FWC / Coast Guard and turn him/her in.