Airtel — Incorrect Billing for International Calls

In the month of December 2009 and January 2010, I made some international calls from Delhi to a Europe mobile number in France.
I got my itemized statement and in this the international calls which are not completed (like user is busy, phone switched off, user disconnect the call) are also get billed.
These calls which are not completed should not be charged. In this the maximum calls of duration 1-10 seconds are the not completed calls which automatically get connected to the automatic answering machine which reply something in french like "User is busy, Please try after sometime" same as it happens here in India for Airtel also.But we are not getting charged for those calls.