When Bell had the $20 unlimited long distance and cancelled it me and my roomie talked up a $800 bill. We called them and told them we didn't know they had cancelled the plan, which we didn't - and they charged us only $20. Then we switched.
There's this site here that lists most of the ISP's, but I'm waiting for someone to switch to a company before I do.
http://www.canadianisp.com/