"Return home" is the wanted answer.
"Come back home" is an alternative.
But why "Go back home" is not correct? It appears on dictionaries.
Come back home is correct and accepted,
the command Rudi works either way, it can mean
Rudi=go back ! or -come back ! (to singular)
rudini =come/go back! for plural
I wrote "Rudi return home" and it should have been accepted. It said to type it in English but did not say leave off Rudi.
Rudi is the verb Return, Nyumbani=Home