They've been having issues in general with the segments around Montreal. These are managed by other companies, so it's a bit of a blame game going on at the moment. It's not up to your ISP, and not SE (in this particular issue) to resolve it--it's a 4th party that needs to come to the table.

We've been trying to get traces of people's routes forwarded to both their ISP's and SE in an effort to get someone to lean on those groups, but have yet to see/hear of any progress. Lots of threads have gone up over the last couple weeks, some are still on the front 5 pages... too many to try to link here. But if you want to find them, might be able to get some hits on a few specific words like Latency, Cogentco, TATA, and i-Web.