If you updated the information on your website, but these changes won't appear when you share something new from your web with Facebook (thumbnails and description texts of shared articles), it is because Facebook has its own memory in which it preserves the information about your website.
The reparation is simple: in Administration of your website, you just need to click on Properties of the page you want to clear (with blog, you need to clear each individual post, next to which you will find the wanted button as well) and then click on Clear Facebook cache of this page.
That will redirect you to the Facebook Debug service. The URL of your page is already filled in, so you just need to click on the "Debug" (or "Fetch new scope information") button.
You will then on the following page see what Facebook sees. As for the update itself, you can't change the content of links you already shared. The reparation will only show with new links.
After the debug (or reupdate) is done, you can try to past the link to your website to Facebook again - new, updated version should show up. If that won't happen, it could be because of a temporal Facebook error. If the trouble will continue, contact our costumer support.
