Understand one thing, plain and simple, it's them who issued you the visa, it's them who will grant you the study permit at POE, it's their very own system. In fact, it's a failure at their end by not being able to deliver you LOI, not your problem at all. That's why I said, send them an email regarding the same and take a print out of the same showing you sent them an email as well and didn't receive any revert when you reach at POE (in case LOI is being asked for). You are playing safe this way, aren't you?
Rest, what I said in PM, is more than enough for you to be relaxed and pack your bags.
Welcome to Canada.
Cheers!