Hathway boradband hyderabad - Harassment by making calls and slow internet speed

In the month of March I opted for Hathway broadband service; * months package for ****rs. They promised for ***Mbps but it was never more than **Mbps, most of the times, specifically during my working hours, I used to get *Mbps. I filled so many complaints and made so many calls to the customer service but it was not useful.
After * months, that is after package is expired, they are harassing me by making so many calls to renew the package. I work in a night shift, my sleep is getting disturbed when they call me.
They even said that they got new plans with better service for *,***rs. So again I opted for new connection. But again I am facing the same issues (low internet speed). It is effecting my work and heavy loss to my business.
I tried calling them so many times but there was no response and raised tickets which has not solved yet. But they are still calling me for renewing the old connection.