Badal Cable TV Network - Service not provided

I paid Rs. **** in advance to my internet service provider on **-May-**** for a * months internet plan. My internet stopped working on *-June-**** for which I informed their lineman and the person who takes payments. They did not resolved my complaint and then I sent a screenshot of my problem to them on WhatsApp on *-Jun-**** and started chasing my complaint by calling them on mobile phones and sending messages on WhatsApp. Finally, they said that the problem can not be resolved and they started trying to sell me another fiber based connection. I urged them to fix my existing connection or refund my Rs. **** because just ** days ago, I had paid them the fees for a period of * months. They offered me a refund of Rs. ***-*** which I refused because the amount was not sufficient. Now they are not answering my calls and messages.
I want my entire amount back including * months fees, interest, legal notice charges and all other penalties that they are bound to pay me for this kind of harassment.