Message Blocking activated but I can't undo it

When I try to send text messages to my son and/or his wife, I immediately receive the message that Message Blocking is active.  But when I look at the list of phone numbers that I HAVE blocked from texts, phone or FaceTime, their numbers do no appear.  This only occurred after I purchased the new iPhone13.  Previous to that I have had no issue in sending texts to them.  I am able to send texts to my other contacts.  The only unique thing about my son and daughter-in-law is that their phone numbers are in area code 630 while their sisters are in area code 616.