Did the fee show up in your latest bill yet or was it just a roaming warning email?

Hi ​@shuotong an we’ve checked the charge you mentioned and as it is accidental roaming we have added a credit to your account, you can check it out in your self serve. 

To avoid future charges please make sure the data roaming is turned off in your phone settings and you are manually connecting to the Koodo network.

For more information on how to prevent accidental roaming charges, please check out this article https://community.koodomobile.com/plans-services-232910/easy-roam-understanding-how-you-will-be-charged-while-traveling-7811296