Are my neighbors pulling a prank on me!?

Print this and show it to your Grandmother. Let her get with the management of the Apartments and they can find out if your neighbors are Pranking you or not. I live in a motel, and I swear I can hear other people snoring when they sleep, so I agree with you that walls are sometimes lacking proper insulation. I wonder if you were able to sleep in a different room would you still hear them. You also have to consider that sound not only comes through walls, but also heating and air conditioning vents. When I was in the Air Force, and I lived in the dorms. We could hear the people on the first floor talking in their rooms and we were on the third floor, but the sound came through the vents. It is a tricky question, but your Grandmother is the person to help you. Peace be with you.