Well I used tata indicom sim many years as it was cheap to buy those days. easy to get not much formalities to get the sim because of that many sim were issued on fake identities as well which was solved many years later because so many crimes happened as per that. tata indicom came to number one when they offer a plan in which you can talk to anybody for 10 minute and only 1 rupee will be cut from your balance if you talk more then 10 minute then extra 1 rupee will be cut for next 10 minute. when they removed this plan after that this company was getting down and down as customers were expecting them to bring the plan back but company lost many users