Shopify support has been refusing to resolve an issue that Google Support told me needs to be fixed by Shopify Support, that I am unable to fix. This issue is preventing me from being approved for Google Shopping as it's due to a third party app used by Shopify. When I delete an item from my store, it doesn't get deleted in the API Feed and the Google bots try to crawl the deleted page of the items unsuccessfully so it gives a 404 landing page error for that deleted item. Google Support told me I cannot fix this, Shopify Support needs to do it on my behalf, yet over the past month I have been jumping through hoops with the runaround on how to fix this by Shopify Support. They have never addressed the solution Google gave me, that I passed onto them. Now they are telling me to hire an expert! WTH?!?! This is so insulting to my intelligence now.
Google Support wrote to me what needs to be done, "....talking about the items to be removed from the Merchant Center Feeds, you just need to have the feed file opened and remove the item/product details from the feed file. Since you're using Content API wherein, we do not have much scope to perform anything for you, as Content API is the third party feed, which is handled by Shopify. You just need to share the ID's with them to remove the items from the Content API feed and ask them to re-upload the feed again on your behalf." So why won't they fix this?!
I have exactly the same situation now, and after reading your post, I lost the desire to contact the support service, since apparently they really don't care about it. I also see that your question has not been resolved. Now I can also say that the Google Channel plugin that I uploaded to my shop has caused me damage in monetary terms. What happened? I just had to stop my company (paid), because the company began to be duplicated, and sending data to Google Merchant is not very high-quality, as was written by the previous user above.