Canada Post is starting to frost my weenie!

Fair warning! Right now I'm rather cranky.
So I went to the post office today to return to a fellow a mailer tube of drawings that he has kindly lent me for a future Yarmouth Model Works project. At the same time I purchased another mailer tube to sent a copy of the drawings to my buddy Aaron.
Now the tube was mailed to me from the US for a tad under $4.00.
Imagine my shock when the clerk informed me that postage for the tube was going to be $17.00, plus another $1.75 surcharge for it being a mailing tube.
I was also informed that the tube I had just purchased was over length, thus subject to a premium charge.
Given that the originals were not mine I felt I had to return them in the condition I received  them in, but the other set were quickly folded and stuffed into an envelope and mailed for $4.00.
So let's review;
Canada Post sells over length mailing tubes that they really don't want to be bothered with and charge more than 4 times the US rate for handling said item. And they wonder why they continue to lose market share.