Bell with line thru it in contacts

I’ve been trying to send a text to a friend. Instead of going as an iMessage, it says sent as a text. But it never actually goes through. When I try to call the phone it goes straight to a fake voicemail message. This person can contact me anytime. I just have no way of getting through to him. In the past we text and talk consistently. When I pull the Contact up, it has a bell with a line through it next to his name. I cannot figure out how to get it off of there or what it is. Please help