Don't discount someone making side money doing washing for others...

Whatever you end up doing, do not stop chasing this including having your relocation agent continually involved. If you stop "complaining" the landlord and the agency can say you resolved your issue the next time you call them and it's a new problem.

Don't feel guilty about continuing to pursue until it's resolved. Things work differently here than in the US, you are not being a bad neighbor. Now is the time to set the understanding that you know your rights and expect others to give the same respect they expect from you. If it was you making the noise your neighbors would not hesitate to enforce their rights, under Canton law, to have quiet after 10pm.

Good luck

Wow -- I would never have thought about doing other people's wash. And, thanks for the encouragement! I have been losing steam, but have renewed vigor to keep up the pressure until the problem is solved.