How can I get reinstated after resignation due to harassment?

I am a Medical Representative at a pharmaceutical company. Due to mental harassment and toxic behavior from my manager, I resigned. During this period, my manager manipulated the system. I gave notice, but I later realized it was part of a plan by my manager and colleagues. I requested to withdraw my resignation, but the HR and sales teams are passing the responsibility onto each other and denying it. How can I get reinstated to the same job?