[Resolved]  Airtel Postpaid — pending payment

I had airtel postpaid connection number [protected] and AcNo:[protected]
I have closed this connection. After nearly 4 months I get a letter of pending payment. I asked for bill details. I receive a mail saying that our executive will give you the bill details at your postal address. We have not yet received any bill details from Airtel and yesterday I recieved another warning letter from Airtel regarding the pending bills. This time the amount is also different.
For further clarifications they have given 2 numbers in the letter viz [protected]/[protected]
I tried this number several times but no one is attending the call.
I need the bill details as the pending amount in very incorrect. I need to tally this with already submitted bill receipts.
Please make sure that you have send in the bill details before giving us any letter of pending bills.