First, the record demonstrates that the appellant's claim for modification of child support was decided following an August 12, 1992, hearing, which had been scheduled pursuant to a rule nisi order to hear motions of the parties that were not related to the claim for modification. The appellant thus did not receive notice that her claim for modification of child support would be decided at that hearing. This lack of notice constitutes reversible error. Royston v. Royston, 236 Ga. 648, 650 (225 SE2d 41) (1976); Herring v. Standard Guaranty Ins. Co., 238 Ga. 261, 262-263 (232 SE2d 544) (1977). 1 Furthermore, the trial court erred by ruling that the appellant was forever estopped from bringing another action for modification of child support. See Conley v. Conley, 259 Ga. 68, 70 (3) (377 SE2d 663) (1989); Livsey v. Livsey, 229 Ga. 368, 369 (191 SE2d 859) (1972); OCGA 19-6-19 (a). For these reasons, we reverse the judgment of the trial court.