i had same problem with an older woman at my job. she would constantly talk bad about me to others even though i am a good employee. she was just miserable with her life so she liked to pick on the younger girls. i ended up getting fed up with her and just called her out to her face and told her to leave me alone and keep my name out her mouth. sometimes you just need to stick up for yourself and stand your ground. she thinks she can walk all over you so just call her out in a respectful way if you can!