I use an Android phone but many of my friends and family have iPhones. Starting a few months ago I discovered that several people sent me text messages that didn't go through. And after digging into the problem, I discovered that their messages appeared as blue on their phone, not green, indicating that iMessage didn't convert it to a standard text. Then I discovered that (at least for some of the people), their texts were being sent to my email, not my phone number. The weird thing is that I don't even think some of these people had my email.
I do have an iCloud account because I own a Mac, and somebody has indicated that can lead messages to your email address. But I'm not sure. How can I, once and for all, deregister my email (not my phone number, that's already been asked) from receiving iMessages and have my friends' Messages apps only suggest my phone number as a destination to text me at?
tl;dr: My email is registered as an iMessage destination, but I need to deregister it so my iPhone-using friends only send SMSs to my phone number.
Just to be clear: This post is not a duplicate of asking how to deregister your phone number from iMessage. I never had an iPhone when iMessage existed and when I try using the deregister iMessage page it just says my phone number is not registered with iMessage.