Denial of Experience Certificate from the Employer

An educational institution is denying the issue of experience certificate to an employee, who has worked for three years and currently relived from all the duties/responsibilities in the institution. The principal of the college has sent (via. email) a show cause notice to the employee, after relieving her for the institution, for which the employee has replied promptly. The show cause notice states that the employee has made false statements against the principal (who has demanded all the employees in the college to bring in at least two students for B.E admission in the current academic year or else face termination - above mentioned the statements by the principal has been digitally recorded). Apart from this, the employee has faced difficulties in running the central govt. funded research project as the college was non-cooperative. The employee has also been demotivated,demoralized and also humiliated by verbal abuse by the principal in the faculty meetings. Moreover, the AICTE norms of payscale has never been followed and the employee has worked without any increment for the past two years.The cumulative effect has forced the employee to submit resignation and finally has been relieved from all the duties. But the management denies all the wrong doings and it has told the employee that it has not instructed any demand for bring the students, which is totally false. Now after relieving from all the duties where is the necessity to send a show cause notices, which the employee feels is all a kind of harassment and moreover, after nearly three weeks of relieving still the experience certificate has not been issued. Kindly advise the necessary legal action that can been initiated to get the experience certificate and also to address the show cause notice which states that the employee has defamed the institution name by the employee allegations in the resignation letter.