BSNL Broad Band Absurd Billing

On April I posted an article about Absurd Billing system of BSNL Broad Band. Now this is the second part of their drama. Last month my father received a call from BSNL, that they made a wrong bill for my connection and only Rs. 2012 is the exact amount for that bill. So they told me that what I payed for the month of April that is excess payment and they will adjust it on my next bill. I received the bill for May of Rs. 1167. I payed before the due date. Now from the last Monday, my internet connection is disconnected. After asking to the customer care I come to know that my connection is temporarily disconnected due to the not payment and told me to contact my local AOTR of BSNL. My father went to meet him yesterday at Mullick Fatak, the Broad Band section of BSNL at Howrah. He clearly told that I must have to pay the outstanding Rs. 3045 of the bill of April which was Rs. 6090. As I only paid the first installment of Rs. 3045, my connection is disconnected. My father told him about the call from BSNL for the wrong billing and submit all the documents in proof. But he denied, he told my father “I dont know who called you up; may be its a ghost call”. He threaten my father that, if I dont pay the rest of the amount within Monday, my internet connection will be permanently disconnected.
This is BSNL, The one and only Broad Band provider undertaken by west Bengal Government. and this is how they run their monopoly business.