How do I explain to a prof who is not happy with my actions which were simply a mistake due to miscommunication?
Agree with Dave, as supervisor/student relationship is like a marriage, communication is essential for it to remain healthy.

However also note that, since you have emailed him quite a number of times and he never responded with any feedback, he did not want to help you, and hence he might not be the kind of person you want to work with. There is nothing worse than a bad supervisor in academia.