Just complementing Teacher´s reply, here some guidelines to go by.

It´s about time people in our country go assertive as consumers, instead of reacting to the products shoving/forcing them down our throats. 

The same  goes for English, cars, cable TV, credit cards firms, cell phone carriers, what you have.  We see plenty of complaints everywhere, including in the Reclame Aqui site, etc... to (almost) no avail.

There´s a long way to go when it comes to consumer rights in Brazil. And it´s not only about English courses, but including them as well.

In fact, we have consumer´s right in paper, but not much of it in practice.