FedEx may, as the shipment agent, collect applicable import duties levied by your country, on behalf of the relevant government agency. The notice is sent to you after delivery of your package. This is not a fee paid to miniDSP, it is a tax imposed by your government.
Note that you can also estimate Duties/VAT from here
https://www.easyship.com/en-hk/duties-and-taxes-calculator/canada