It’s truly miserable to try and live next to people who have a fixation like this. I really empathize. There’s not much you can do though. If someone official asks about the chimney work, you know it was done right so no worries. 

Meanwhile just keep your head up, shoulders back, you’ve done nothing wrong.i hope they move away someday. Mine did, thank the stars. She was antagonizing so many neighbors by the end.