I tried the *#7780# code followed by 12345 as the default PIN but I was told that the PIN is wrong. What do I do now?
Since it's impossible to recover the PIN, you will need to send the phone to the warranty service or visit a service shop. The technicians have custom hardware components used to decrypt the phone's security.
There is no way to recover or replace the PIN without a hardware box. This can be done at a phone service shop because the box is too expensive for regular user. They can also perform a master reset of the phone.