Hathway — Legal notice for not returning modem - Hathway-[protected]

Address:

Chennai

My hathway broadband account - [protected], I was using hathway broadband for 6 months during lockdown(March to Oct 2020), then i had to shift house. When i informed them to collect the modem, nobody turned up for almost a month. So i left the modem at the old house when vacating in hope someone would come and pick it up.But after 2 months the house was locked and the owner is now out of station. Now im getting calls/mails from hathway to either return their modem or pay fins of Rs. 2500 else legal notice would be sent to me. I never signed any agreement that if their modem is not returned after disconnection, i will pay the amount of 2500. Also while acquiring the connection along with the prepaid bill amount i paid 400 as deposit. There was never any mail or return communication regarding the modem and its agreement. But hathway is now harassing me through mails and phone calls. What should I do. Please help