I have taken many tours from Tamil Nadu tourism( ttdc). I booked them online. I wanted to cancel one tour "Half day Chennai tour". For this I wrote a mail to them and even got a response, which is good. But they never credited the money back to me bank account as they promised. Other I booked a Taxi from ttdc from chennai to Pondicherry.
Taxi was as per the expectations( AC and a good driver). Also booked the Mahabalipuram resort for one night on the way to Pondicherry. The rooms were not maintained. They have a huge property in Mahabalipuram on the beach which is good. The location is good but the place is riddled with bureaucracy( if you ask for something it will take a lot of process and time) and shabby maintenance. Better to go in for face to face booking than online booking if you want to have a cancel option later and not run around for your money.