I regret you felt uncomfortable during your visit.
As someone who is a native Quebecer, and fluent in French and English, I welcome anyone's attempt to speak in either language when in Canada.
Unfortunately there are yahoos everywhere in the world. Sounds like you met some of 'em.

However, American money is not legal tender in Canada.
It's a courtesy when Canadian businesses accept it, but you should not be offended if it's refused.
Canadian banks generally convert foreign funds to dollars, for a small fee.

Hope you come back and visit again. Most Canadians (and Quebecers )are polite and welcoming to visitors.


RichM