to take more serious action about sth or speak to sb at a higher level about it :
I am not satisfied with your explanation and intend to take the matter further.
to take more serious action about sth or speak to sb at a higher level about it :
I am not satisfied with your explanation and intend to take the matter further.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005