Have you contacted Facebook Customer Support and or your network customer services to rule out that they are not blocking anything @Margaret2019 ?
To rule out the Samsung phone can you try your sim card in another phone as a process of elimination.
Daily Driver > Samsung Galaxy s²⁴ Ultra 512Gb ~ Titanium Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
