Hey @kaitlinsherman ,
Was ACT! able to tell you more about why they thought it was a WooCommerce issue? If they did, those reasons might give insight for what to check.
I did look over those instructions. A couple things do come to mind that you may be able to check.
Make sure your API Key is set properly with Read/Write permissions: https://swiftpage-docs.cloud-elements.com/docs/services/woocommerce/woocommerce-endpoint-setup.html
You may have to generate a new key to make sure it’s set up right. Also, on the latest versions of WooCommerce (starting with version 3.4), the API keys are under WP Admin > WooCommerce > Settings > Advanced > Rest API.

Link to image: https://d.pr/i/aM7p2I
You can also test the API itself to make sure there’s nothing blocking it. There are details for running those tests here: https://github.com/woocommerce/woocommerce/wiki/Getting-started-with-the-REST-API
Given the screenshots on that page, you may also want to try the Legacy REST API. If that works, be aware that the REST API is deprecated and should be removed from WooCommerce soon. ACT! should update their integration to use the current API to ensure it continues working in the future.
Hopefully that gets you going. Let us know how it goes!