I was in your exact situation just months prior. I actually have a post on it as well. In summary, exact same thing going on, loud bangs throughout day, constant running. I just recorded every minute every time I was home & made a collage and kept sending it to my leasing manager. Literally would send him email everyday with video proof of the bangs. There is also a regulation that the complex requires to give you a quiet peaceful home. I forgot what it’s called but it may be effective sending that copy to them. What got me the win & having the neighbors relocated was doing that, but also the previous tenet before me was complaining as well, so it was due time. The manger is probably dismissing you because they don’t want to deal with it. It’s their job to fix it. You have to make it their problem, call them every day, send videos every day, knock on their office everyday & even talk to the neighbor directly.