International roaming charges without picking call. Review on Airtel Mobile Operator

I have been charged by Airtel India, huge amout of money ~3K, for the calls I never picked while my travel in USA from India for a couple of months.. Airtel in turn has been charged by Cingular-USA Network.

Customer service persons in india simply don't have any explanation about this? They don't  know how Cingular USA can charge this money. To my surprise all these call are of duration less than a minute.I am sure there is some default settings when we are on CingularUSA Network which are activated automatically , they can be like automatic answer  key on?? ?? ? ?? ??

Does any one know  how it is possible technically ?

I want to suggest onw should be aware of such rules....

Pls let me know.

Thanks for clarification , Sanjay

I have been charged by Airtel India, huge amout of money ~3K, for the calls I never picked while my travel in USA from India for a couple of months.. Airtel in turn has been charged by Cingular-USA Network.

Customer service persons in india simply don't have any explanation about this? They don't  know how Cingular USA can charge this money. To my surprise all these call are of duration less than a minute.I am sure there is some default settings when we are on CingularUSA Network which are activated automatically , they can be like automatic answer  key on?? ?? ? ?? ??

Does any one know  how it is possible technically ?

I want to suggest onw should be aware of such rules....

Pls let me know.

Thanks for clarification , Sanjay