If I quit with understanding from the owner of business. Is the manager allowed to lie about my leaving?

I had recently quit a job. Now as I am trying to get new employment, my old manager is extremely lying on reasons why I left to ruin my chances of employment. I do have doentation from one prospective employer. Can I press charges and/or file a civil suit against her for slander/defimation of character and if so what else? Please help. I have been unemployed for over 2 months due to this action.