How to import/restore .vmg SMS backup to Android?
I recommend you to try Import SMS from Windows Phone app. It imports unlimited SMS messages from both .vmsg and .msg. It is free and you can find it on Google Play Store.

If you have MMS messages or group conversations to import, try the PRO version, called Import SMS from Windows Phone PRO. It also imports unlimited MMS or SMS messages, but is a paid version. You can also find it on Play Store.