Small matter like this wanna sue here sue there meh?
Pos Malaysia and Air Selangor not gonna care much lah.....

Get a plumber to fix loh, perhap Rm 100 or so, then put some barrier to prevent other people from knock.

if got budget then some metal barrier
if no budget then some flower and its pot.

Also u sure Pos malaysia or not? we dont have that many mails these days. perhaps Lazada, shopee, Grab food?

u know... u may demand compensation but they taichi push drag dunno until when leh