Idea Cellular — ignoring the benefits they given to me

once idea cellular offered me the plan which suits to me and they also told me i hve to pay 250 rs for security its refundable whnver i changed the plan ,but after 15 days i switch to another plan i asked for the security money but they simply refuses from the security money now they are saying that u r charged for the sim ,but they already taken 250 extra for this.my no is [protected]