New HTC One messaging issue with iPhone

Alright so I've never had this issue before. I often switch back and forth between iPhone and android often but this time I'm not receiving any texts from my friends who have iPhones. I can text them, but when they respond it goes as an imessage and I don't get anything back. I have gone on my mac and turned off imessage completely, and also turned it off on my iphone completely. I also turned off the iphones wifi and of course removed the sim so it has no connectivity. I have also had a couple of my friends go into their contacts and make sure my number wasn' listed as an "iphone" in their contacts and it was rather just mobile. All things in check, and I still can't receive texts.

Does anybody have any ideas what I can do to fix this? If there aren't any fixes I'll have to return the phone and go back to the iPhone.