Best Answer: The deadline for an employer is to send out the T4 slips to employees by midnight February 29th. So they still have a few days to put your T4 in the mail.You can start to prepare your return especially if you use software enter the forms as you receive them.ou have to wait until after the February deadline to contact CRA. A week into March to allow for delivery time at least. Then you can contact CRA and ask them if they have the T4 on system from the employer.