Rant: Got a call from Asianet Legal Team on pending dues even after their broadband service was disconnected.

This is the second time I'm getting getting a call from Asianet and the first time from someone claiming to be their legal team telling me there are pending dues even when I cleared them all before disconnection.
I had sent them an email for disconnection and got an achknowledgement email (this was back in 2023) from them saying that it has been initiated. However last October(2024) I got a call from them saying I have pending dues to which I clarified that I had already sent the email they asked for disconnection and got an email back from them. I sent them an email again just in case to make sure in case they missed it.
Today afternoon I got another call from someone claiming to be their legal team saying I have pending dues. This struck a nerve and I told him sternly that I had already disconnected from them and soon it turned into an argument and I ended up losing my temper with him (I know I shouldn't have, but I hadn't slept properly in a couple of days due to work and was taking a well deserved nap when he called).
In the end the guy kept saying "give me proof if you have proof" several times and like that he cut the call.

Seriously the absolute worst broadband service I've used so far. Has anyone else faced this issue with them when you tried to disconnet?