Oral defamation or libel?

Good day.. Now ko lang nalaman na yung isang co worker ko (higher position than me) gave a written report to our higher management acussing me that i had sex with a client namen.. Pinalagpas ko nun tinawag nya daw akong whore (as per one of our co agent). In the written statement of her, pumasok daw ako mag isa with a client and had sex sa hotel which is absolutely false because when the client invite hindi lang ako ang kasama at di lang ako magisa kundi lima kame and we had dinner lang.. I am a mother of 3 and i felt na nasisira reputation ko sa opisina namen. What case can i file against her. I have the copy of the said written report. I wanna know din the chance na i can win the case ad what penalty dun sa nanira sakin.. Hoping for your great help guys and soonest reply.. God bless and thank you..

you can file a case of libel, but she will be allowed to raise the defense that it is qualified communication because it is a report to authority. it will depend on the how you present your case, what words she used and the appreciation of the prosecutor whether the case will prosper.