USPS International Letter Missing After Failed Delivery Attempt

My letter with tracking number RR960403837TR could not be delivered to its address in the United States. When I check the tracking information on both the PTT and USPS websites, the latest update says that the address could not be reached and the letter was redirected to another address.
If the letter could not be delivered to the original address, why hasn’t it been returned to me yet? I respectfully request that my letter be returned to me as soon as possible.



