Pricing - Anamolies . Review on Airtel Mobile Operator

I am a new member and I am writing the second review. Yesterday I cribbed about the Stupid model of Sony Ericsson 300i . Now I have a few serious questions about Airtel's (Even Hutch ) pricing model. The TRAI regulation is pretty clear about Advertising the tariff rates and transparency in the system. Just today I saw the prepaid tariff for Chennai Circle and thought I would recharge for Rs 150. The table boldly mentions the Validity for this as 30 days . So I paid thru my internet banking with HDFC. My account was recharged, but the validity had not been extended. I called up the customer care and a confused representative was telling me that I should go out and buy voucher from some retail shop for getting validity. Then my friend told me that there is a concept of "Topping" and "Extending Validity". I again called up Airtel's wonderful customer care and another gentleman told me to recharge for Rs 200 if I wanted the validity. This I did through internet and Lo the validity got extended. There is another funny twist to this, my friend said I could buy a coupon for Rs 250 and get the validity and that is better since the frequency of toppings would be less.But this is not happening in Internet banking. and only talk time gets increased without validity.

I dont know what is the point in discriminating between buying coupons and recharging thru Internet as in either case I am shelling out the same amount. Another doubt is why is the minimum recharge for chennai high (Rs 120) . For Bangalore and some other circles the minimum is Rs 54. Why is this discriminatory pricing? I feel the system is very loose and TRAI should tighten its hold on the telecom operators. Customer is highly exploited. Another menace is unsolicited advertising through SMS .