In its biggest-ever crackdown on a ponzi scheme, the Securities and Exchange Board of India – SEBI on Friday ordered immediate closure of unauthorised collective investment schemes run by PACL Limited and refund investors' money within three months.As per Sebi's order, the total amount mobilised by the company comes to a whopping 49,100 crore rupees collected from around 5.85 crore investors. The case dates back to February 1998, when SEBI ordered PACL to neither launch any new schemes nor continue raising funds under its existing schemes.SEBI sources said it has asked the company to wind up all its existing Collective Investment Schemes and submit a winding up and repayment report to it. Besides, SEBI has also initiated proceedings against the company and nine of its promoters and directors for fraudulent and unfair trade practices.Meanwhile, facing a Sebi order with charges of running an illicit money pooling scheme worth about 50,000 crore rupees , PACL Ltd on Friday said it will approach the Securities Appellate Tribunal against the directive of the capital markets regulator.