Universities offer degrees. Business English isn't a degree program. If you want to take a Business English Program then you should be looking at colleges (not universities). Yes - colleges will generally accept you with IELTS scores of 5.5 (you should make sure that you have scored at least 5.5 in each of the four IELTS categories - if you have scored less than 5.5 in any category, that could be a problem).