I have the "Multichannel for WooCommerce" or Codisto Channel Cloud plugin.
Keep in mind this is an official WooCommerce plugin and works with many other 3rd party plugins.
We run an eBay store as well as Woo. I have got it to sync in terms of updating in Stock Central > Codisto > eBay. But when it is the other way around eBay Order > Codisto > Stock Central ATUM doesn't update the stock levels.
When an item isn't managed by ATUM, the sync is successful. But when it's Managed by ATUM it's not successful.
I know there are a lot of 3rd Party Plugins out there and its difficult to make sure they all work, but Codisto is a very popular plug-in and if it isn't working maybe you could talk to the devs as I love using ATUM.
Please advise 😄