You’ll have to check the last page of your bill one month before the increase to see the notificaiton for a rate plan increase. It is also possibly 3 dollars a month if you have a phone that uses 3G data or doesn’t use VoLTE. Koodo has added a 3 dollar a month surcharge to anyone who still uses the 3G network. It should show that in page 3 detailed billing if that’s what it is.

To add to Goran, whilst you’re in self serve it may not hurt to see what other rate plans Koodo has available to you. Its likely that you can choose a plan that is either cheaper or the same price that provides a lot more than only 8GB for the same cost. Just be mindful that if you change your plan, proration charges will show up on your next monthly bill and you will have a prorated amount of data until your next cycle. More information can be found in the link below 

https://www.koodomobile.com/en/help/changing-your-rate-plan

For 10 years my bill has always been 50$ monthly. I have never had issues with Billings.

I have lived at my present address for 5 years.

In the last 6 months I am continuously being billed for roaming in the US, when I have not been there.

Now I see an extra charge of $ 4.96. What is this charge? 

I recommend you download the latest PDF bill of this month and the previous month and check the page 3 (and 4) of it to see the detail breakdown. If your rateplan was increased, check the last page of the previous month PDF bill. There should be a notice there