How is independent contract work with an agency (match marketing group) for a temporary sales position filed?

It depends. Are you self-employed/freelance? How did you get paid - did they give you a t-slip? Did you have expenses?

This CRA page has a guide to help determine if you are an Employee or Self-employed: https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/rc4110/employee-self-employed.html