It not possble to menatin one no. in india..

If you are fed up by compony offer calls then you can activate Do Not Disturb service. which free of cost i think for all cellular cariers. I think by the time i have started using mobile phone i have changed 1000 mobile numbers. Don't know why but some how i have reasons for all of them. Mobile Number Portability (MNP) is also an option you can adopt for if you are very much fed up with the company you are using. Like if you are customer of Vodafone like me then you should be getting at least 10 promotional calls every day. So MNP is the option you can go for. By keeping the same number but changing the mobile compony/cellular carier. If you suffering from anyother problem which is not getting solve by the above methods than you can call the customer care executives for it. I know only two of them vodafone - 111 and Airtel - 121.

In that case MNP (Mobile Number Portability) may help... I guess you know it.. With the help of MNP which is recently launched all over India you can change your service provider without changing your cell phone number... you have to pay a small amount (19 rs mostly) to enjoy this service.. So i guess its good if you want to swap your telecom partner and choose any one which better suits your usage... Have a good day.. :)