Hathway — legal notice for not returning modem

I have been using hathway internet for a while now. My current plan expires only on 27th jul 20. Since i was shifting my house - i raised a request[protected]m839017) 2 days prior shifting to check on the feasibility of connection at my new place on 20th may. I dint get any response, i shifted my home as per plan on 22nd may. I called them several times, at last 6-7 engineers have contacted and told me that its not serviceable in my area. I then wrote an email on 25th may to appellate authority asking for refund if service is not provided. They later confirmed that they cannot refund and today i got a call from a lady stating they cannot refund but need the modem, i asked them to provide the balance amnt and can take the modem (Its with me), she said they ll send a legal notice