Not able to cancel the policy in Freelokk period

Location/place: Hyderabad

Name of company/service: ICICI prudential

Dear Sir,
I took a policy from ICICI Prudential during the Mont of December 2011.I recieve the document on 10th of April 2012 through DTDC shipment No-H98174837 and my policy no is 16289453.It is written than I got a freelook period of 15 days to cancel the policy within the 15 day of recieving the bond.
I wnton to cancel the bond on 11th of April(next day of receieving the policy).But they are saying that the freelook period ha been expired since the policy was receieved by somebody Mr.Naidu during Feb 2012.Please help me to cancel it in Freelook period.