The 866-310-1023 IS the official number to call SO customer service.
The 866-310-1023 works for both Canada and the USA. I have called it for my Canadian account, as well as my American Speak Out account. When you call, they always ask for your Speak Out number, so they know which account to look at.
Also, I don't know where you got the 800 number but the 866-310-1023 is the correct number to call the Canadian CS, as stated on their website:
http://speakout7eleven.ca/pages/contact/