Have you always fed her F/T or did you previously feed live?

Sometimes Ball pythons will go off feed for no appearent reason, but males will mostly go off feed in the Winter. Also, I would give her a week each time you try feeding her so she doesn't get overly stressed. If she takes it and constricts it I would close her tub and leave the room. Maybe turning off all lights would be good too because they are nocturnal and normally hunt during the night. Check back on her in an hour or two and see if she took it down or not.

Sometimes Balls gotta have their privacy when they eat. Whenever my Ball pythons take the F/T food and constrict it I just put the lid back on and go to the next tub. After they all get their food I stack them back up and let them be to eat in privacy and to digest.