My ‘Phone’ app is sending me spam messages

See above screenshot. I received a notification from my ‘Phone’ app (NOT my ‘Messages’ app) of a spam message. How is a spammer able to send a message through my ‘Phone’ app? I don’t even have an option to block this sender because there are no contact details associated with the notification? Has my phone been hacked? Any advice?

These types of spam messages tend to be malicious in nature so I’m not sure how to ascertain if anything has been compromised

[Edited by Moderator]