Is it fairly new? When we lived in SC, folks were trying anything to kill them...grits seemed to work consistently...blew ‘em up.
Don’t have a problem here in the desert with fire ants, but the carpenter or argentine are a nuisance...get into food if it’s not secure.
I get it from Wal Mart.
I’ve been using it for several years now so it’s not new.
Have you tried 7 Dust?
If you can find where the carpenter ants nest is a few shots of carburetor cleaner does wonders and it’s a lot cheaper than termite killer.