You’re correct of course. This is the HST (Harmonized Sales Tax, since I’m also in Ontario) which is basically what we call it instead of VAT.
I didn’t really realize I’d have to pay this when I originally ordered, but on reflection I should have known this. Most of my online purchasing lately is unfortunately Amazon, which through their Canadian site forces the sellers to register and collect and remit the taxes at time of sale. It’s been ages since I bought something where I had to pay the tax on delivery.