But this situation is basically a problem of the post office, and it is difficult to find the responsible unit. First of all, it is difficult for you to find the registration issued by the correction. Even if you find the registration, the post office insists that the mail has been sent there, and it is difficult for you to find evidence to prove that it is the other party's responsibility.
I suggest that if you don't receive the notice of patent correction now, the first thing you should do is to apply for patent document reproduction immediately and ask the patent office to send the correction again. You should hand in the revised documents within the time limit first, and then investigate if you really want to find out the reason why you can't receive them.