https://www.canada.ca/en/employment-social-development/programs/ei/ei-list/tax-slips-itemized.html
"If you choose to receive your T4E by mail, or if you didn’t select any delivery option on your EI application, your T4E will be mailed by February 28. If you don’t receive your T4E by mid-March, contact us." https://www.canada.ca/en/employment-social-development/programs/ei/ei-list/tax-slips-itemized.html#h2-02
https://www.canada.ca/en/employment-social-development/services/my-account.html
contact https://eservices.canada.ca/en/service/