Nextra Teleservices Pvt. Ltd. - Internet not working issue

I had taken Nextra internet services on dated **-**-** from their sales guy Amit with Package buy * months and get extra * month free and got my internet installed next day even after several follow-ups.
After installation after * or * days, I faced internet not working issue and got a solution every time more than ** hours despite multiple follow-ups.
now my internet is not working since Friday night ie.**nd Feb **** and still it's not working. I had already tried raised concern with their customer support team Abrar and all other guys and always got fake commitments that it will be sorted in next * hours and so on even I had sent mail to their escalation departments as well for a refund but till now not received any response. Their technical guy name Goutam Kumar Roy visited my place day before yesterday to check the issue but till now he is not able to track the exact issue. I also had a discussion with their technical head Rahul as well as well and he committed that issue will be resolved by yesterday EOD but till now no one turned up.
Request you to kindly look into the issue and get my refund done. I have attached a payment receipt for your reference.