Start with the part that is verifiable
Separate the event you can describe from the motive or reaction you are guessing. For a message about how to apologize for damage caused by your pet, use this factual base: state the date, place, property, noise, pet, or shared-space impact without arguing about the neighbor's character.
Make one answerable request
Give the recipient one concrete question or next step instead of several emotional jobs at once. Offer cleanup, replacement, access, a schedule, or another practical remedy you can complete. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Leave the recipient in control
Do not threaten, shame the neighbor publicly, or involve the whole building in a private issue. Use property management, local authorities, or emergency services for genuine danger rather than confronting someone unsafely. A clear message remains useful even when the answer is no or no answer arrives.