Yes, foreign nationals have the right to file in US courts, and a binding arbitration agreement that bars foreign nationals from participating is invalid as against public policy and he could file in district court.Sometimes a cigar is just a cigar. Sounds more like a bad print that was corrected.
If your brokerage agreement allows for arbitration - then file an arbitration claim. Not sure if a Canadian can request NYSE arbitration.
File a written complaint with the NYSE. That opens a file which will trigger an exchange compliance person to investigate the situation. Make sure your complaint is in writing with a copy to your broker, the SEC and the CSA. When the SEC does it's audit of NYSE/ARCA one of the first things they look at is the open compliance files and the length of time taken to close a file.
Is your broker an exchange member ? If not also include their order consolidator in your complaint.