Recharge voucher 27 rs

Dear sir/Madam, yesterday in the airtel mobile I have an offer if I reacharge with 27rs I can call to karnataka,andhra & kerala for 30/Min, so I have rechared with the same amount and have recharged with 20 rs top up, but, when I call to andhra pradesh, they have charged 1.50 piase/Min instead of 30/Min, how cheap the airtel people are when I was asking them about this to the customer care, 2 times they have lifted the fone they DID some acting and they say anything, and after they when ever I was trying it is going to automatic machine isted of the representative, why this sutomer care ther for, what the hell these people are doing this,why aitel is mainting customer cares in chennai, dame worst, in andhra the customer care is too good we never faced the problem.My main concerns is that the airtel chennai customer care should work for the people else they should close the care center.