Duo makes me crazy. Sometimes we are required to give the word by word translation. Other times we are required to give the English meaning. I know that in English "coming and going" is the accepted phrase, but put "going and coming" because that is the literal translation. I was marked wrong.

True, and that is accepted but there is not another way to express it without being deceptive. Both "were coming and going" and "were going and coming" are accepted in English. In French, use "allaient et venaient". You could also say "were going back and forth".

The present tense conjugation for "les anes" would be "vont et viennent", but this sentence is in past tense (imparfait).