So its a long shot but this device worked for me and my dog she only barked while we were out of the house annoying our condo neighbor, and then my coworker got one for his three dogs who were barking at new dogs over the fence.It stopped the barking on both sides of the fence, they would still whine/whimper a bit but it really helped.
When we bought ours we were assured by Petsmart we could return it if it didn't work.
Also we only leave it on when we need it so she doesn't get used to the sound and start ignoring it. I swear it cured her separation anxiety related barking and really helped her be less anxious when we were out.
I have a hard time letting a device do the training for me but when the behavior only exists away from your presence I was at a loss as to what to do...