iMessage allows users to send texts, documents, photos, videos, contact information, and group messages over Wi-Fi, 3G or LTE to other iOS or OS X users, thus providing an alternative to standard SMS/MMS messaging for all users with devices running iOS 5 or later. Therefore, you cannot receive iMessages. Only SMS/MMS. Have you tried sending a message while the phones are side-by-side just to see if you really aren't receiving any SMS/MMS?
I have never had an IPhone and all of a sudden i am no longer able to recieve text messages from Apple phones. I have had my galaxy for over a month and never had this problem before. Also someone else is recieving all of my messages and she is getting really mad!