Have you possibly blocked them? To check, go to your contacts app, click on the person in question, press the three dots and if it says "unblock contact" then this would be why
On Google messages, click the circle on top right and tap on 'Spam and Blocked' is the contact there?
Would be really helpful to tell us what you've tried so far... saves our time so we're not suggesting things you've already done. My mind reading is disabled today 🙂
🤣🤣 I have tried all of most things I have got google messages also normal messages which I have done and checked all it has asked me to do am not really sure what I'm doing tbh what is RCS ???
Is anyone else not receiving this one contacts message or is it just you? It may have something to do with RCS (Rich Communication Services). You could toggle off RCS chats or you could you try swapping to Samsung Messages and see if it resolves your issue.