post somebody somewhere：把某人派往某地；打发某人去某地。例如：

Jackson has been posted to Hong Kong. 杰克逊被派到香港工作。

《21世纪大英汉词典》

Where is he being posted? ---Oh, somewhere in the Far East.

《现代英语用法词典》（张道真）1996版

I’m afraid Captain Jones is no longer here: he’s been posted away.

《现代英语用法词典》（张道真）1996版

所以，get sb. posted 的意思是“把某人打发走”。