An auditor is black mailing our company

Dear Sir, I am a director of a Pvt. Ltd. Company (Manufacturing Unit) based in Delhi. I and my wife are Directors of Company. My current (2015-16) turn over is 32,00,000/-. Company is 8 years old. Now, My auditor is trying to exploit us. He does not give us and data (Books of Accounts) of the company except Balance Sheet and P & L. He has not completed our sales tax assessment even FY 2009-10, 2010-11 , 2011-12 and till date. He had not even filled Balance Sheet in ROC for FY 2014-15. We are under small scale industries. Now, we do not want to let him give our work. We asked him to return our all document and his resignation so that we can appoint a new auditor. Now, he demanded 1 Lac (approx) rupees as fees. We got shocked because we have already cleared all his dues whatever earlier decided. He told that the amount is outstanding in the financial of 2014-15. The balance sheet that he had given us there was written a word 'Other Liabilities' that covers his outstanding balance. His firm name was not mentioned over there. I am a technical person (Engineer) and do not have such knowledge. Even that I agree to pay this amount (not paid yet). But even after he is not ready to return our file and give resignation. Please give us proper guidance. We are not able to understand what to do.