Tikona — Broadband service

I took the connection back in 2019. After the first year of excellent service, every month, I would lose 7-10 days in waiting for the service engineer to arrive post a complaint. Either their connection line gets broken, or they accidentally shut off your service, or, their modem becomes unresponsive, blah blah blah... Now, last year, I asked for disconnection of the service via e-mail. After that, for the first month, they didn't disconnect, and would call me 7-8 times a day asking me to change my plan (Btw, they were charging me Rs 2, 600 for 10Mbps speed, per month, unlimited). After the first month of disconnection request, they started giving me threat calls through lawyers asking me to pay up for 1 year, and said if I don't pay, they'd block my Aadhar Card for 25 years. I don't even know what that means, and how that can be done. I mailed to them multiple times to take the modem back, and take anything that's there, but they only said repeatedly that my request is "under process". Can anyone please tell me where can I complain, as I am a 74-yr old man, and it's very difficult for me to travel far, or in to courts. Simply put, I can't travel much, and I can't live with these threats from some Priya Aggarwal advocate!