I ran into this too and ended up calling Apple. Their solution was to tell everyone who had my number to erase their iMessage history with me. Somewhat odd - I

I ran into this too and ended up calling Apple. Their solution was to tell everyone who had my number to erase their iMessage history with me. Somewhat odd - I can receive individual texts from two people that have iPhones but if one of them sends a group text to both of us, I do not receive it.