How to apply DND(Do not disturb) officially in Uninor GSM?

Hi,
I just purchased a uninor GSM sim as i heard that uninor gives extra top up and my friend suggested that it has a nice network coverage so i decided to go with it. But the problem with the uninor mobiles is that there are thousands of miss call daily in my mobile handsets and i don't know what to do and what to do not. Please suggest me how to apply the dnd for the uninor gsm sim.

Please provide the offficial customer care number as soon as possible.