Not sure what more I can tell you apart from the details above.
"I changed the listings to free for sellers" Seller's do not need to pay to list their products
"When a seller submits a product " Seller logs in and add a product to their listing
"admin publishes it" Admin log into Sellacious backend and publishes the product (activates product)
"it does not show up on the website." The new product cannot be found on the website
Can you please explain more about this issue and steps?