AT&T's Facebook advertisement on August 19th, 2016
With social media, there is no way to control how consumers react to advertising. Daniel Brewer pointed out the link is broken. Natalie Andrews points out it leads to a 404 error.
Instead of fixing the link, AT&T's responses attempt to persuade commenters to direct message the brand. What the social media team failed to address this: the link didn't work. It was made clear at the very first post, where Natalie Andrews says "Might help me get more prepared if your link worked...lol."
AT&T continues to dig the hole ever deeper with each response. This further damages its credibility for their cyber-security service. While we will most likely never find out how many members of the social media team responded to this, it appears that it is the same individual, just using different names to sign off.
It sounds like common sense, check your work, yet, it isn't so common in practice. Make sure your links connect to the right page before posting to the general public. Failure to do so allows the opportunity for mockery.