What to do if employer refuses salary and relieving?

I resigned from my organization two days ago with a one-month notice period. While I am ready to serve the notice period, the employer is forcing me not to come to work from the next day. However, they are refusing to provide me with a relieving letter, saying they will relieve me only after one month. They have also withheld my salary for the month of June. I told them that if they do not want me to come to work, they must relieve me immediately and clear all my dues, but they denied my request. I am still serving my notice period and reporting to the office, but they are unresponsive and have not paid my June salary.