Employer not willing to pay notice

Did you demand the salary in writing and refused ? If so, move to area Labour Commissioner or raise an industrial dispute u/s 33 of ID Act through a local lawyer.

I have dropped them multiple emails requesting them to pay the notice period amount with no response to it and they have also blocked my Email id. 

Since you have resigned and it is now the employer's choice to relieve you are keep you for notice period. When you had no job option at hand why you resigned .

If there is anywhere stated between you and the employer (any contract, job offer, appointment letter) that you shall work for notice period mandatorily then you can file compliant in labor court.  

I was asked to resign and it is very clearly mentioned in the appointment letter that in case the employer asking to leave when the employee wants to serve notice in that case the employer has to pay the notice period amount. 

Usually, whenever any employee resigns, company withholds employee's salary during notice period and pays it during Full and Final settlement. It is only to make sure if the concerned employee has any dues payable to company, whether employee is giving his charge handover properly etc. before official relieving