Hi there @torch01!
As Facebook has developed this plugin themselves, they also handle the support for it.
You can either find extensive documentation here:
https://www.facebook.com/business/help/900699293402826
Alternatively, you can submit an issue on their GitHub repo: https://github.com/facebookincubator/facebook-for-woocommerce/issues
GitHub is the place where the code for this extension is maintained.
The things they are looking for when you contact them are:
1. Facebook Page URL
2. WordPress and WooCommerce version number
3. Facebook Plugin version number
4. How many products you have
5. Types of products (i.e. anything besides simple/variable products won’t work)
6. Do you have Duplicate SKUs in your system?
7. What kind of customization plugins you’re using (if any)?
Please let us know if we can help with anything else.