It is hard to know what happened. Could you log into your self-serve and download the pdf bill and check the page 3 and 4 of it to see how much Koodo charged you?

If possible, could you post a snapshot of the bill here? Please hide all personal information before posting.

I used prepaid chatr, and at the Filipino party in Calgary in Canada there was a Koodo provider and they told me that if I switched with them they would give me 40GB and unlimited international minutes, I just received my bill for more than 300 CAD

Can you elaborate on the plan? How much was it supposed to be? Did you get a new phone on a Tab? Have you made any calls or sent any text messages while abroad? How many international minutes did you use?