Txt msg not received on Android phone, but Android txt msg to my iphone is received
Had an iphone 5S and used to be able to send to my Dad's Samsung Galaxy S5 android phone txt messages. For about the last 5 months he does not receive my txt msges, but I always receive txt msges from his Droid phone. I upgraded to the iphone 6 and the problem persists. We have tried all sorts of things from txting Text stop to 48369 and they will reply with a text saying you are signed out of icloud. to turning on in Settings, send as SMS. We called Apple and they were not able to fix the problem. They said it was an AT&T issue, our carrier.
My mom and sister also have an iphone 6 but their txt messages are received on my Dad's droid phone and they receive my Dad's txt msges. So the issue must be something with just my associated phone#.
Can anyone offer any suggestions how to fix this? Thank you.
iPhone 6, iOS 8.3