Friend changed from iPhone to noniphone and now not receiving group text

help...

my friend went to the dark side and bought a non iPhone phone. Now we try to group text her from a group of us that used to text all the time and she won't receive any of our meessages because they show up as iMessages which she doesn't have anymore. She said she deleted the whole phone and turned it in prior to leaving store. She can send iMessages that show up as text messages but doesn't receive ouR responses because keep showing up in blue as iMessages. Anybody have any idea what to do? We deleted conversations, restarted phones and all that. Help! She only receives messages when we shut iMessages off on our settings but that's not a thing I want to keep off.