Nextra Teleservices — refund of router is not processed in last 18 months even after 15+ followup calls

Address:

Mayur Vihar Phase 1, New Delhi, Delhi

I had a nextra connection in delhi, there were 1500 as deposit against the router. I had to move pune, so i closed my connection and returned router in feb 2018.
After that i followed up on refund for approx 15 time (Request no: [protected]), everytime i am getting the response that refult would be processed in next weeek but till date i didn't get the refund on it.