Voice and Script International ltd - Certificate not given and stipend not payed after completion of internship

I'm currently a second year journalism student in Delhi University. Around * months ago I applied for an internship on internshala.com as a content writer. I was hired by a company called Voice and Script International Ltd. for a duration of * months starting from **/*/**. A proper contract was drawn and signed by both parties.
Now, after the completion of my internship,there is no response from their side related to the promised stipend and certificate. The person who was appointment as my superior and mentor for the internship duration is neither replying to my messages nor is picking up my calls, and I have no other way to contact the company. I filed a complaint on the internshala website but I'm yet to hear from them.