"Mortgage.ca" is owned by BMO. It does not resolve. Meaning, that the correct spelling of this word is not presently put to its highest and best use; namely, to be a landing page of some sort for a mortgage advertising campaign.
In kind, the traffic this particular misspelling stands to receive is not much as of right now. But I say it's only a matter of time before BMO makes use of the name, and inherently, this one starts getting a bit more traffic.
Remember, people don't know how to spell the word "mortgage". So I'd keep paying the reg fee.