So can she perform Hajj again, does her Hajj not count?
If a woman performs Hajj without a mahram, she is disobedient.
Disobedient to Allah the Mighty and Majestic and His Messenger, because the Prophet ﷺ said: A woman should not travel except with a mahram. Then a man stood up and said: O Messenger of Allah, my.
My wife went out for Hajj, and I was in such and such a battle. He said: Go and perform Hajj with your wife.
But the Hajj is not invalid, meaning she does not have to repeat it, rather she must repent to Allah and seek forgiveness for what she has done.