I agree that it is very distressing to hear a dog left like this - but if you can, why not have a quiet talk to them about what you are hearing, on the basis of you hear the dog and are worried. Which is probably true! They may not know the dog is upset.
We had adjoining neighbours who bought a Westie (despite having been turned down by Westie Rescue as they worked full time). I couldn't stand hearing the puppy crying and in the end, went round and offered to have her during the daytime, if only to give her lunch!! We had a puppy pen to keep her safe in. Eventually I decided she had to get used to their life-style, so she went back to being left far too long, in my opinion. They did buy another puppy but then thank goodness, MOVED.
That property was a nightmare as before those two, we had a single youth who'd come back from work and start playing his electric guitar. In a semi-detached property with full sound!! Unfortunately we couldn't move as we were renting and with no means of buying elsewhere.