Nextra Teleservices — return of wifi router

Address:

110090

I was a student in 2015 and 2016. I was using nextra internet service in 2015 and 2016, when i was staying in laxmi nagar and nirman vihar. Then i have to shift to greater noida west in gaur city in 2016 and i had called nextra for relocation of my internet connection but they told me they don't provide internet service in my new area. I told them ok take your router back and refund my 1500rs which i had deposited as security money for router
After making a request many time on their toll-free no they didn't respond and i waited for many months and then on calling them again i got a email my phone no is not reachable and they were not able to collect the router but they were lying as my phone is working from last 5 years and i had even sent them my contact details via email. I have attached all the evidence below.
Kindly take a necessary action action nextra as they were lying and calling them again and again is mental torture.