Tikona Broadband Service - Money Extraction

I was user of Tikona Broadband Service, using Wi-Fi services for residential purpose. When I had complained on their support emails and phone calls - most of the time network was down / service not available for whole day / line related genuine issues were regular in my area. I had requested to terminate the account and stop the service of Wi-Fi and I was not using modem and internet. Device was disconnected from the Power however monthly bills were generated from 0.00₹ and now increased above 10000.00₹ without using the internet service. Now Tikona company is sending legal notice for money extraction. They have sent a notice to pay the money within 7 days or legal action will be taken. How do I handle this case? I have all proofs of emails / email communication / multiple request of termination however they kept generating bills and looking at their patterns it’s intentional behaviour. Please advise, where do I file complaint / how to take action against this company? Tikona Infinet Private Limited, 3A, 3rd Floor, ‘Corpora’, LBS Marg, Bhandup (W), Mumbai 400 078. CIN: U74899MH1975PTC265837 | PAN: AAACM6427C State Office Address: 3a, Corpora,Lbs Marg,Bhandup West,Mumbai City,Maharashtra,Maharashtra-400078 GST Registration Number: 27AAACM6427C1ZR