The first thing to check is that you haven't accidentally put the contacts into your phone's call blocking feature and that the contacts themselves haven't added you inadvertently to their call blocking feature @lacey
As a process of elimination can you try your sim card in another phone and then ring them.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb.
Samsung Gear s³ Frontier Watch.
Samsung Galaxy Watch⁴ Classic.
The advice I offer is my own and does not represent Samsung’s position.
I have no affiliation with Samsung.
