I didn't! I believe in the possibility that the OP DID properly file a counterclaim, however, it still got dismissed by the judge because the one who initiated the claim (Plaintiff) requested dismissal without prejudice. Obviously, the judge may have felt there was no merit in the counterclaim and that's why he dismissed it. It is for the OP to initiate a new lawsuit if the OP wants to address claims raised in the Answer that he filed. And if the Plaintiff, who requested dismissal wants to file again, they could, since it wasn't dismissed with prejudice.
Please read Rule 41 of the Rules of Civil Procedure.
A voluntary dismissal by the plaintiff is dismissed without prejudice (the
first time). "Unless otherwise stated in the notice of dismissal or stipulation, the dismissal is without prejudice ..." A plaintiff does not have to request the "without prejudice."
A voluntary dismissal by the plaintiff cannot defeat a counterclaim by the defendant that was already pleaded. "If a counterclaim has been pleaded by a defendant prior to the service upon defendant of the plaintiff's motion to dismiss, the action shall not be dismissed against the defendant's objection unless the counterclaim can remain pending for independent adjudication by the court."
No one on this forum has seen the claim or the counterclaim so there is no way anyone on this forum can say whether ufgirl "did everything right" (although Georgia's forms make responding to a complaint with an answer and counterclaim about as easy as it can get).
And no one on this forum can get into the head of the judge, so there is no "obviously." The counterclaim may have merit.