Previous employer didn't send my T4 and did not answer my request at all. I am almost done for 2017 except for T4. Can I file without T4?

If you are registered for the My Account service on the Canada Revenue Agency, you can log in and see if your T4 slip is there.  If you are not registered for the My Account service, you can contact the Canada Revenue Agency at 1 800 959 8281 and they will provide the amounts to you.