Hacking a facebook account?

A person who is probably a competitor of my brand left a negative review about our brand in a facebook group and that post ranked very well on google even though the review is full of lies. Facebook support is of no help, even though we have attached all the necessary documents and evidence to them. I am wondering if there is any way to remove someone's post in a facebook group? The admins of the group don't respond to messages, I can only think of hacking Facebook and deleting the post. Anyone have any ideas or suggestions? Of course I pay for the service