Send short messages appropriately.

You can find the local post office, which is the sender's post office. They have a receipt to prove that you sent it. This is the problem of post office delivery.

As for why? Generally, it is the following situation. First, it may be invested in the unit, and the unit has a mail room to collect it. Second, the community doorman did not inform the residents to pick it up. Third, the delivery was wrong and was thrown into his house. Fourth, there is an agency where the consignee is located (for example, my university has an agency). EMS is based on the time when it is handed over to the agency. There is a record on the Internet, but the actual agent has not sent it to the recipient. 5. The consignee received it but said it didn't.