How to block lost mobile phone

Hi

I have lost my Nexus 4 mobile phone in bangalore india.

any body know how to block the mobile phone, so that it will become of no use.

I asked service provider TATA DOCOMO in mathikere, bangalore but they says,they can't block it.

also contacted LG service center RAJAJI NAGAR bangalore, and they replied same.

please let me know, if any body know how to make that lost mobile phone uesless.

Thanks