Re: If we have IMEI no. of our window phone it is possible to recover
If you have set up your Windows Phone with a Microsoft Account, then visit your Windows Phone account
here, then near the upper right corner of the page click on "Explore" or "My Phone" (or your name, your phone name if you have previously logged in to this page), then click on "Find my Phone". You will be prompted to log in in the process.
In the page the comes up, you will a list of your Microsoft Devices, and where they were "last seen" and the time when it was last seen. Should you wish to get an more updated location for your phone, then under each phone there's an option to "Find My Phone".
Note, however, that the location was the last location information the phone uploaded. Depending on the settings you chose in your phone, this could be either continually updated if your phone is off or it could be the location where it was last turned off. These mean that the location will not be updated if the phone is turned off and when it has no data connection (e.g. when the SIM has been removed).
Regarding using the IMEI, you may contact your mobile service provider and have them perform a trace of the location of your phone if it is turned on - within the provisions of your local laws, of course. You may also ask them to block your phone so that it can no longer be used by whoever would not return it (this can also be done through your Windows Phone account).
Let us know what you find, and welcome to Windows Central - sorry to hear about the news of losing your phone though. Let's hope that it can be recovered or will be returned.