But now I'm using my SIM card in an HTC phone. The problem is people with iPhone still see me as being on iMessage and when they text me, the text is sent via (blue) iMessage and not (green) SMS. So now on my HTC phone I can not receive any messages from iPhone users!
I've turned off iMessage on iPhone AND iPad. Logged out of all iCloud related services - iMessage, FaceTime, iCloud, iTunes...
I've deleted my iPhone from my Apple ID Profile online.
But people with iPhone still see me as on iMessage! What should I do to permanently remove my phone number from iMessage service?