Tamil Nadu Arasu Cable TV corporation is a government-run cable TV service to provide people with cable services at affordable prices. There are press reports requesting people not to pay for the setup box (https://timesofindia.indiatimes.com/city/chennai/set-top-boxes-free-do-not-pay-operators-arasu-cable/articleshow/60905757.cms).
Firstly, please consider is it worth the time and effort. Such irregularities happen in places. Secondly, please check whether you filled in a form for getting the setup box free.
If you want to proceed with the complaint. Please discuss with your homeowner and the cable guy informally and agree for a simple solution. If not then you can consider the following.
Please read this consumer document that has clear details (page2-3) about how and when to complain regarding tactv services. (https://www.tactv.in/pdf/consumer-charter.pdf)
Alternatively, you can contact them via the grievance section.(https://www.tactv.in/grievance.php)
The contact details for tactv is as below
Tamil Nadu Arasu Cable TV Corporation Limited.,
Dugar Towers,34 (123) 6th Floor,Marshalls Road,Egmore,
Chennai - 600 008.
Phone :+91-44-2843 2911
Toll Free :1800 425 2911