Shows price less in flight network site and charge...

Shows price less in flight network site and charge more than 2.5% of the original price. One type of cheating with customer.
I booked my flight with Flight network booking ID no. 7955887 and 7947237 date May 06, 2019 and May 09,2019 as on Canadian dollar.

Flight network booking id . 7955887 flight confirmation no. QVG08N
I booked two tickets with Canadian dollar 340.35 per person and when I checked my credit card payment details on same date it shows me 348.98 per person..

Flight network booking id . 7947237 flight confirmation no. ZYBT0N
I booked four tickets with Canadian dollar 731.93 per person and when I checked my credit card payment details on same date it shows me 751.04 per person..

My question is that I booked in Canadian dollar price and why should you charge me 2.5% transaction/ conversation charge.
With other site Expedia.ca never charge like this.