Reliance GSM Communications — Call rates over charged

Address:

Visakhapatnam, Andhra Pradesh

My name is D. Hari Prasad,
I am using Reliance GSM mobile, no. [protected].

I called to this no. [protected] on 10/12/2012 at 3.45 PM and I talked for 15mins, and then I called other several numbers and those are as follows [protected], [protected],[protected], [protected], [protected]. I called these numbers before 4.30 and after every call message balance was being displayed except for the first number which I had dialed at 3.45 PM.
At 4.30 PM I got a message from Reliance that Last call charge for 1.30 mins was RS 28.
Logically I cannot call another number in between 3.45 PM to 4.30 PM if I am talking to a person. The dialed history displays that I have called other numbers as well.
So my question is how Reliance GSM services has deducted my money when I was not on call for 1hr and 30 mins.
I called to the customer service and they simply neglected that it is not their fault. They denied to refund the amount back.