[Resolved]  Hathway Cable & Datacom — asking for bill payment from 2017 when i was not their customer

I received an sms on 26th september 2018 asking me to make a payment for hathway bradband bill from january 2017.
I was not a resident of the address mentioned in the bill in january 2017 and wasn't a hathway customer at that time. When i got the connection disconnected in mid of 2016, i informed them about the same. So they did not send any bill after september 2016. But suddenly sent one again in january 2017 (Remember that i had informed them about my discontinuing the connection in 2016 itself). Post that they did not send any bill as they knew that i wasn't a customer anymore. So now, they are threatening legal action via sms for a connection that did not exist at the time of the bill and for an address where i did not reside at the duration mentioned in the bill.
When i go to their website and enter my details, they notify me that my account has been kept on hold at my request. I did not make any such request and had asked them to close my account and connection in 2016.
Client number: [protected]