Idea Sim Card — block the sim

I lost my Idea sim card in a train journey. The sim card is of Kerala. But I am not in Kerala right now. So I sent a mail to idea service center to kindly block the sim. But they are refusing to do so although I am ready to give my full details to them. They are saying that they do not provide the service of blocking the sim. So the option left for me is to get a duplicate sim card for the same number. and for doinng the same I will be charged some Rs. 150/-
How can I get another sim if I am not in the state. If some illegal thing happens from the mobile I will not be responsible for that. I request idea to please block the sim. Just for the sake of not loosing a coustmer they are trying to bind me.
Name- Vaibhav Dixit
Father's name- S P Dixit
Mobile no- [protected]
Address- IIST VSSC campus, ISRO Po Veli, Trivandrum

Kindly intimate me about the action taken.