Hathway Cable & Datacom — wrongfully billed after two years of service disconnection

Address:	Hyderabad, Andhra Pradesh, 500090
Website:	www.hathway.com/Broadband

I've used hathway internet connection for two months in 2016 jan and feb and my account number is 1505127. I had a lot of disputes regarding their billing, they charged more than the plan i opted for. So i have requested them to disconnect and changed to another provider.
After two years, now they sent me a legal notice stating the bill due is 13934
That's a whopping 14 thousand rupees for the service i haven't been provided. I called the customer care explaining the issue their response was blunt telling me to pay the bill regardless my connection was on hold. Adding to this my account number has been changed to [protected], i don't think account number can be changed for a customer.
I've been waiting for their billing department to respond and resolve the issue but no show from them, meanwhile i'm getting messages regarding the legal notice.
To put it simply "hathway" does not have a proper structure for anything and the worst customer support i've ever seen.