no response on resignation by the employer

I'm working with private limited company. I've resigned and completed my notice period. There was no response from the company at the time of resignation. I'm still with the same company trying to get relieved but they are still not entertaining me. I need to get out of this company with proper documents like relieving letter etc. As there is no response on any of my action from the company, I'm stuck here as I've no relieving documents. I'll need those whenever i find the next job. Please suggest a solution.