On IPhones when you go into your cellular settings you can turn of a certain apps access to data. You might have disable the data for safari if you are using an IPhone.
It can take from a few hours to a business day to port a phone number according to whistleout. If it hasn't gone thru by the end of the day you could try reaching out to koodo.
Yes, it can be used to pay for your phone plan as long as your payment is less or equal to 50 dollars. If your plan is more than 50 dollars you will need to top up your account.
It’s probably a good idea to avoid this as others suggested. Make sure to never give out banking details to untrusted websites. If you purchase stuff online using an account like PayPal is also a good idea just to be extra safe.