Hathway Hyderabad - Exploitation and bad service

I took a new connection on December **th, ****.Total amount paid is Rs.**** (including three months charges). Promised internet data was ****GB per month and a speed of ***mbps. Exactly from January *th, ****, there was only connection but no internet data. After multiple calls to Hathway customer service, no solution till now. They only apologise. I couldn't attend one important job interview which was to happen online. There was a high probabality of me getting that job but I lost it due to bad service of hathway. If I would have attended that interview, my CTC would have been ** Lakhs. My loss is that much because of this issue. My life is on the line. I need internet to search for jobs and attend interviews online. That was the main reason I took this broadband connection. But Hathway took money for three months and not willing to return that little money also. I am really fed up and depressed as I am not able to attend interviews. I still didn't cancel the connection, because they said they wont return the money. But there is no internet as well. They are exploiting people very openly. Taking money and not providing service. Please help me. Hathway should return the money after cancellation or fix the internet connection problem ASAP.