Ah..the disappointment. I know how you feel. I have 2 female kitties that I introduced slowly and they still don't like each other. They tolerate each other but still chase and swat at each other, at least once a day. I was hoping some day they would get along. I am not holding my breath for that, a friend of mine had 2 females cats, they have had both for years and they don't like each other, never have.
I may be adopting a male cat this weekend, this boy gets along best with females so I am hoping it will calm my ladies down.