Hathway — Threatening for legal notice

I have requested hathway to transfer my existing connection to new place where i was shifting. I waited and followed for 1 week and then opted for new connection. I have informed hathway team over email and over call to disconnect the connection. I have never heard any thing from them from dec 2020 till march 2021 for returning modem. I am receiving call to pay 2 month custody charge and then i have to return modem. I have told them that i am willing to return modem but they are asking me to pay the money. I have request with hathway but they are closing the request and calling me from random numbers and threatening me for legal notice.

There is no customer care to speak and raise our concern and why should i pay money as legal charge even i am not opting the service. I am mentally disturbed and i may raise complaint with police if harassment continues.