Turns out it was partially a mistake. $18 for HST, $11 for duty, and $10 'handling'. The HST is fine, the handling is BS, and the duty is an error because the box was classed as "lightbulbs" (8%) rather than "computer equipment - keyboards" (0%). At least I know it wasn't opened... I'm not sure if it's worth my trouble to try to get a refund for the duty now that I've already paid it though.