I filled out a “Application for Leave” form
June 4 to June 8 2018.
The paperwork was approved.

June 7 I was terminated.
They called it Job Abandonment.

What can I do?

Based on your synopsis, the company cannot terminate you for job abandonment and you are entitled to a severance package based on your age, position, and length of service. Please use the following link to determine your entitlements (http://www.severancepaycalculator.com/) and then contact us at the number below for a consultation with a lawyer.