Google penalty, resubmitted tons of times but nothing works

Hi, I work for a company where our health website got a manual action penalty months ago and we cannot fix it. We took down all of our old articles, plus our commercial articles, and produced new content. Should we keep our old articles, too? I'm not the boss of the situation but it's getting pretty desperate. Right now our action plan includes creating a new domain and moving our articles there but I'm worried we will get a Google penalty again if we don't know what we did wrong in the first place.