You have mentioned your notice period is 3 months and notice pay claim for 2 months.Pls check your appointment letter.
How did you send your resignation letter. Have you taken an acknowledgment.
You may write to your appointing authority or Managing Director of the company, and reiterate on your resignation from the services mentioning clause in your appointment letter vide which you can terminate the contract by giving a notice for ....months or salary in lieu of that.
You may ask them to send you by registred post,the acknowledgment of your resignation letter,acceptance of resignation, work experience certificate, PF accumulation report,Form16,PF withdrawl forms ,and write to settle your account, and advice you to whom you should submit the company property ,if any with you e.g computer, I. card,Visiting card etc ,on a mutually convenient date and time and venue( Prepare an itemised detail in advance and obtain receipt duly signed and stamped by the competent person). You may keep in touch with the concerned superiors,HR in this company and complete the handing over formalities at the earliest, and maintain cordial relations.
You must have secured another job.In new company complete formalities of submitting the employment form with testemonials,copy of your resignation with acknowledgment, and obtain offer letter.Clear the situation ,tell the HR person the old company is not willing to relieve you and handover the copies of your letters with copy of regd post receipt. New company may conduct reference check with your past employer, on telephone,by email, or through a consultant. Be careful, and give proper references. Find out from your new reporting authority/HR that it is positive while you join.
Attrition and Job opportunities are both a problem in the Industry. Hence the situation.
Be smart and Manage.