Charged me for internet service which is not working

Location/place: Hyderabad

Name of company/service: Excel media

Dear All,
I took an internet connection with excellmedia, their office is located at banjara hills.. I took the connection 4 months back.. The connection doesnt work at nights and on sundays.. I made payment for six months and after repeated complaints it is not rectified.. And they are not even ready to refund..Kindly help me out..My no is 8179289280…my mail id is [email protected]