CRA Contact has been harder these last years. Less phone agents are available now as the CRA is pushing for a CRA My Account. By signing up for a CRA My Account, users are able to us this service for many different ways. Saving copies of your Notice of Assessment, making adjustments to past tax returns, viewing if your return has been filed and or processed, and many other activities can be done on your profile.
Please read the originial post here: https://accufile.ca/cra-contact-information/