Natural antifungals only kill certain strains of yeast. It may be that you don't have those strains of yeast any more. It is also possible that your yeast has developed resistance to those particular natural antifungals. Many people believe that yeast develops resistance to most natural antifungals in a matter of weeks.
Do you get die-off on GSE? This so-called natural antifungal kills most yeasts and I don't think is as prone to resistance issues. However be careful that you use an effective brand of Grapefruit-Seed-Extract like Nutribiotic. Some Grapefruit-Seed-Extract brands are 'too natural' and don't work.