Hathway broadband bangalore - Phone call Harrassment to customers who left Hathway

I had to leave hathway and find another internet service provider when i shifted house and hathway was not operational in the new house area. From that time, i have been receiving weekly * calls from Hathway to make payment and rejoin them. I told many times that i'm not interested, but i receive continuous calls every week. They don't unsubscribe me from my calls. My Hathway account id is **********. I need to stop receiving these nuisance calls. Inspite of repeatedly informing them not to make calls, they do it.