Hathway — Getting calls about fine for not returning router

The house owner has discarded the router. We had already paid a security deposit for the router and we don't expect that money back. But now I am getting calls asking for Rs. 2500 fine or monthly fine, etc which is totally unacceptable. Please call me in [protected] and help resolve this issue.

I have 2 hathway accounts and I am still actively using 1. Kindly provide good customer care to your existing customers!