You shouldn't let a coworker sabotage your job.
Jan who is frequently bullied by her coworker Meg, finds out that Meg deliberately tanked a project Jan was working on.
Jan wants to respond to Meg's actions.
Jan reports Meg's actions to her boss and files a complaint.
Jan tells Meg she is sure it was a mistake and that she will try to fix it.
Meg is censured and her performance put under scrutiny.
With no fear of consequences Meg continues to sabotage Jan's work.