How to Guarantee Top Comment in Facebook?

Hello! I am trying to sell some items in a specific niche. On Facebook, I follow a figure who is very closely related to my niche, and has millions of followers. I have notifications turned on in Facebook when that figure posts, but never seem to catch it as it only hows up within facebook. Is there a way I can set up a text alert, or another way to be guaranteed to be one of the first comments so I can ensure I get plenty of free exposure?

Thanks!

Hi , I have a script for that. Care to JV with me?

Sometimes there is a facebook setting for a page that sort comments by newest, not by popularity