So I recently asked a girl to text me, and I put my email on her phone, but she never texted me because it said "not registered with iMessage" even though I am. Then, I asked her for her phone number and when I tried to text it, it said "is not registered with iMessage". We both have iMessage and we both made sure we gave each other the proper address. I have an iPad mini 1 and I think she has an iPhone 4 or something. Can anyone help me with this???