For some reason when I use the Messages app to send messages app to send iMessages to people, I get no notifications when they respond. But here's the weird part. It's only for ONE PERSON. Whenever someone sends me a message, it will always show me a notification except for this one person that I message, in which it will not show it to me. I've tried deleting the person's contact card and recreating it, all to no avail. Please help.