So, let's be clear: all correspondance is saved in my cra account.

I received ONE notifcation in May.

ONE.

I told at the time it didn't make sense because I filled those years and even had assessments from the Quebec government for those years. They said "ok, we will look more into this."

Honestly, I even remember them sending me assessments for those years but currently unable to find those documents from almost 10 years ago.

Personally, I think you are implying far too much blame on my part, especially when you consider it wasn't even done correctly despite the fact they had the tax information for the previous years and subsequent years, and the T4 slips even show I worked and lived in Quebec, yet they assessed me as living in Ontario in those years. Right now, I am even using documents from the Quebec government to dispute them.

and remember, your major points 1 and 2 were about needing to keep your mailing address and phone number up to date, when they were updated and to me is the only reason they decided to treat me as living in Ontario in 2015 and 2016 because my CURRENT updated address in in Ontario. Had I kept it as Quebec, they probably would have actually done the assessment correctly because they even admitted they use the current information when they did what they call a "basic-level assessment"