So I just got my samsung galaxy S7 edge yesterday and i few people when they texted me their messages only went to the iphone 4g that I have. I already went to my iphone setting and dissable the imessage but i havent got any messages in my new phone.
Google "iMessage removal tool" from your S7 and use Apple's tool to instantly de-register your phone number from iMessage. You should be good after that.
If you still have your iPhone, go to Settings, and turn off iMessage while the phone is connected to the Internet. Then give it about 20 minutes to register.