Nextra Teleservices — Company not issuing refund for services not used

Address:

Nextra Teleservices Pvt. Ltd. in Udyog Vihar, Gurgaon- 122016

I had been facing connectivity issues with nextra broadband since a very long time. Their services are pathetic.
I had recharged my internet connection yesterday on 3rd December 2020 at 7 pm. At exactly 10 PM the internet stopped working and there was no connectivity till 3 Am due to which I was not able to do my office work. I called the customer services today and did put in request to stop my connection immediately and refund my plan amount which was paid just yesterday of 648 Rs. The customer care person simply denied for the refund even if I was not able to use the internet. Please help me with the refund