Do not worry too much. I mailed a package on 7/16 too.

The relatives have not received after three weeks. I took my mail receipts and customer form and went to the local post office. Based on the CSW# in customer form, the worker in post office printed the trajectory of the mail and it was surprised that the mail was delivered on 7/28. I provided the CSW# to my relatives and they went to the local Chinese post office . After many calls, my relatives located a local company who claimed that it has tried to deliver the package , but there was nobody at home at that time. Of course, they delivered the package finally. It turned out the Chinese post office outsourced their package delivery business.