If you're unable to locate your project or access coursework or tools associated with a paid plan, there is a good chance that it was created in another organization. Since you can belong to multiple organizations and maintain projects in any of them (given the proper role) this can cause some confusion as to where some projects are created.
To check if a missing project is in another organization, you can switch to it by selecting "Switch Organization" in the dropdown available in the top right corner. You can switch to any organization you belong to at any time. Once switched into that organization your projects list should refresh and show only those relevant to that organization.
When you click on "Switch Organization" you will be greeted with a modal that includes a list of organizations to which you currently belong. From there, clicking on the organization name will take you to that organization and the corresponding projects.