Hathway Broadband Internet - Broadband Internet advance paid for one year but harassment since 3 months as internet is npt ava

I am using Hathway Broadband service. I had opted for the yearly package, of which i had paid ***** (aprox) advance amount for ** months package.
Since * months, the service has been pathetic , and i am being harassed.
Just once in these * months, a person came to change the modem, but still the problem persists.
There is practically no connection all day. And even if there is internet working, the speed would be *mbps, whilst my high speed plan of ** mbps.
U just end up struggling * mins with IVR options to talk to a poor helpless guy at call centre, who just assures that someone will definitely help you, but no response comes.
Rather a text would come, "we tried to call you, but you didn't pick". How funny can that be.
Else , if we raise a ticket on HATHWAY MOBILE APP, without addressing your complaint, the ticket will close automatically in a few mins.
We really don't know, how to talk to someone who is incharge of broadband division.
Even tried mailing, but just in vain.
Kindly help if u can.
I don't want this Hathway connection, and juat want refund .
Thanking you
Gagan Chopra
Hathway Customer id: **********