IDEA MOBILE - charging Rs 6.40/m for std call

i am usumg idea sim (9921346196).When i am calling back to a STD landline no.from which i got incomming call ,they were charging Rs6.40/m.MY std tarif is 50 p/m .For this compliant i called to customer care no 1234 and to 198 and gone to My idea shorum also.when i am going to 1234 they will direct me to call 198.If i call to 198 they tell me to call 1234.By doing this i got to complient no which is 1-663618224 &1-748626779.they were tell inhg that " i am dialing 00 infront of std no",But i am not dialling 00 .i am just redialling the incomming no from my mobile which is staring from +91.

I suspect this problem started from 20 th jan 2010.Uptill now more than 100 rs they diducted from me.I kindly request to investicate the matter.