how is their customer service. - as any customer service, i use them just to make a complain, take the complain number and follow up with the back end team on my own
-any downtime - yea i had some issues first few days ( some error at their end, sorted out.) + every 12 hrs there is a forced reconnection by them. Once in few days (maybe 5 or 6 days.) its down for 20-30 mins, starts back on its own. I have taken the number of tata back end office @ salem, and they resolve the issue immediately) Since you are in Chennai, you may have better service.
-2mbps truly don't have any FUP. just curious. no FUP. thats why I opted for this
-I've been informed that telephone connection need's to be requested separately and Rs100 /month is charged for the same. - No. And i got a free DSL modem + router ( not a big deal, but free is free boss)