Mahindra Finance — NON ISSUING NOC

I have already settled the amount for the contract account no.1293490 by cash Rs. 66, 040.00 to be received by the Thiruvallur Branch Manager Mr. A.Maayandi dated on march29, 2014.He agreed this amount and also he gave the settlement letter through mail with his signature. In that letter, He note that the NOC will be issued within 21 days. But till date I have not receive the NOC from Mahindra Finance. After that, I contact maayandi through phone regarding NOC but, he asked to pay further Rs.12, 000 extra amount. why should I pay for that amount? I have already settled the amount and also i have the settlement letter and the payment receipt. Gave me the reply for this message otherwise I will go for consumer court .