Wrong carry on bag grabbed Southwest Airlines flight from Nashville to Austin Sunday Feb 8

Posting here because Southwest Airlines can't do anything since it wasn't checked luggage. Filed a report with Southwest. Wrong blue Away suitcase grabbed from overhead. The new assigned seat policy is creating havoc and Group 2 boarding the plane now has to go back several rows to find any overhead space. Wrong bag was grabbed at landing. We have the other person's matching suitcase and there is no identification inside or outside the bag. Can describe items in our missing luggage, and there are unique identifiable items in the luggage we have that could help us make sure we find the right person. Open to any suggestions if anyone has gone through something similar before!