Can't receive SMS texts from one person

Hi

I have an Iphone 8 and I cant receive SMS messages from one person. I have tried the following fixes

1. deleted the contact and added them back
2. updated the phone so everything is current
3. Deleted the conversation
4. closed all the apps
5. restarted the phone
6. reset the network on the phone
7. double checked the contact information is correct
8. checked i am not blocking them

We can call each other just fine and they are receiving my texts but I am not getting their texts back.

Any suggestion on what is the problem?

Thank you