Good question! I'd be happy to take a look and see what I can do to help. There are a few potential causes for your product catalog menu appearing in the top left-hand corner of your product collection page. But I would need to take a look at your store to isolate the issue. Would you be able to provide me with your store URL as well as the name of your theme? Even a screenshot of what you want reverted back would be useful!
If there is anything else I can help you with, please let me know.