My Japanese neighbors frequently complain about noise our family makes

My family of five relocated here four years ago and have seen many tenants move in and out of the opposition apartment.

A childless Japanese couple moved into that apartment six months ago. They have a dog, and often leave their accommodation in the morning for work before coming back at 1 p.m.

They mostly stay all the time in their apartment and do not interact with others in the neighborhood.

I have three kids aged nine, six, and three respectively. Children of these ages often talk loudly, cry, and fight. We also talk and watch TV, which obviously makes noise.

We leave our apartment door open sometimes for the kids to get in and out easily, but I think its soundproofing is still good.

So, I don’t understand it when that Japanese couple complains about noise from my family. There was one time when they even came to my door, said things in an aggressive and impolite manner, before slamming my apartment door as they left.

I reported the case to the complex’s board of management, and when a representative came to talk, that couple asked them to request my family not to make noise anymore.

I think they are too harsh since my family has always tried our best to minimize our noise. That apartment’s owner said they could not do anything either since the couple signed a one-year renting contract, but I feel really annoyed. I really want them to move out soon.

What should I do?