sorry to hear your demise ..... firstly, as mentioned, wait a couple of more weeks and see if it dies down any.
Then, if not , I would speak to the body corp manager or whoever managers the place ... but he won't understand English so do you have a Thai wife who can speak to him?
The guard would have his contact details I expect.
Failing that, if there's no manager to talk to, maybe look at relocating elsewhere.
Don't confront them yourself, it'll only make things worse.
TIT .... they don't care about neighbors and especially farang. Empathy is not in their vocabulary ...