I live in a 4-unit, 2nd floor condo. The air conditioners for all 4 units sit on the roof. One of them sounds like the compressor is going out. When the unit cycles on, the sound/noise rumbles and rattles throughout my kitchen. It's horrible. Through a process of elimination I discovered it belongs to the neighbor below me. We DO NOT have a good relationship because part of my floors squeak and wants me to stay out of certain parts of my home when she is sleeping. Not going to happen. The HOA won't really help. They sent over our maintenance man who knows nothing. My neighbor is lying and saying it's not her AC. HELP! I don't know how to proceed. Any suggestions?