Skyline Networks - GST Fraud Evasion

This is in reference to a business in Mira Road by the name of Skyline Networks.This company runs a very large Internet and Cable service in MIra Road.In my building of *** flats alone they have Internet and Cable connections of *** + consumers.The minimum month charge for any service with them is *** per month.I opted for an Internet monthly service package ( **mbps ) for *** every month.My office is willing to refund this monthly Internet payment because of the Work from home scenario due to COVID-** that i pay to Skyline and they need a bill/receipt for the same.Ive been asking Skyline networks to provide me a bill but they have repeatedly refused to do so over  several conversations over the phone/in person at their office and Whatsapp chats.Whenever I ask for a bill they say we have not charged you GST of ** rs per month so a bill cannot be provided.I have told them to charge the GST amount and provide a bill if that's what it takes but they still refuseI'm suspecting huge tax evasion in terms of GST and Personal Income Tax by the owner. The owner is Amit More and is never available.The office is run by three employees Jameel.Elisa and Sonam.This business has a huge monthly and annual turnover based off the Internet/Cable Connections they have in my area and many other parts of Mira Road.In short Im reporting GST Fraud/evasion along with Income Tax evasion.Kindly assist.If there is any other help needed from me please do let me know.These are the phone numbers to Skyline Networks - **********/**********Owner- **********
Thank You,
Kavita Abraham