Mailchimp custom module issue with syncing old data

So the client wanted to be able to segment clients based on the purchased brands
So we found that we can send the brand data with a custom module so that the client can segment using vendor purchased option

I created the module and tested it locally and all was good
But when I deployed to production. Nothing is happening because the products are already synced to the production mailchimp account

What can I do. Clicking on resync clients is not fixing it
How can I make Magento/Mailchimp resync all products