It is a known matter that now-a-days women some times in order to perform Hajj travel with non-mahrams, even though they have mahrams who choose not to go along with them (for many reasons like work or personal matters).
So is there a possibility that the Hajj of such a person may not be accepted due to this?
It is not permitted for a woman to perform the Haj without Mahram accompanying her. But if she performs the Hajj without Mahram, then she is a sinner and her Hajj is valid. This is the fatwa of permanent committee. See the fatwa here.