1. The statement "Call it a special delivery" is a pun, but your translation didn't reflect the sense of humor.
2. You tend to follow the structure of the English sentences and thus put the subjects and verbs at the end of the chinese statements. It's not very smooth, frankly.
一名邮递员将其应该发送的数十张贺卡中饱私囊,旨在偷取夹在其中的现金,邮政督察员表示。
邮政当局从六月份就开始接到投诉,称贺卡在向布鲁克林一个邮区的居民投递途中发生丢失,美国邮政检查服务特勤斯蒂芬-多罗夫在布鲁克林区美国联邦地方法院的备案文件中这样说。