If you have the same questions as me, this article is to share the method I found and found it actually works!

It is actually very simple to return a letter in Singapore. Usually, there is find a return mailbox like the one shown in the picture in the mailbox of HDB or Condo. “For Returned Mail Only” will be written on the mailbox. You just need to cross out the address on the letter you received, write the reason for the return letter like “Wrong Address” and put it in that mailbox, the postman will handle it for you.

I tried this method for weeks and I do find lesser wrong mails sent to my place!

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