Once you post a vehicle to the Facebook Marketplace (link), the listing will remain until it’s deleted manually. This is true even if your vehicle is marked as Sold in WebManager. 

The Facebook Marketplace Auto-Posting Utility cannot delete listings for you. To delete an outdated listing, you’ll need to access your Facebook Marketplace Listings page, outlined below. You can also renew or edit listings from your Facebook Marketplace. 

Delete, Edit, or Renew a Listing Within Facebook

Access your Home Page by logging in to Facebook.
If you were already logged in to Facebook, navigate to your Home Page by clicking the Facebook logo in the top-left of any page.
From your Home Page, click Marketplace in the top-left.
On the left-most sidebar, click Your account.
You should now see Your Listings. Listings that require your attention, such as a duplicate listing, will appear at the top. 

Next, click the three dots to the right of the listing. A few notable options will appear.

• Mark as Pending: Marking a listing as pending alerts potential buyers that a deal is in progress, but the listing is still visible. 
• Renew: Renewing an older listing will improve its search visibility. You can only renew a vehicle that’s been listed for more than 7 days. 
• Edit Listing: Editing a listing allows you to make changes to an existing post. If you only need to make a small change, such as updating the price, editing the listing means you won’t have to re-upload the vehicle. 
• Delete Listing: Deleting the listing removes the post entirely. You’ll want to delete a listing once the vehicle is no longer available, or before you post the vehicle again through the Facebook Marketplace Auto-Posting Utility.