If your business is on social media and someone starts to disagree or post negative comments, you have a few options. Trolls are everywhere and you almost have to expect them on your public business site. Don't lose your cool. Don't respond with negative comments. Respond with positive comments. If you are a business and don't delete comments that you don't like. Your brand should be displayed in professional manner at all times. Deleting negative comments can make a business owner look like you don't care or have something to hide. You can moderate comments to exclude any posts from being seen on your page. Make sure you monitor and know what is being posted on your business social media sites. You are responsible. Post Positive.
If this is your personal social media site, the same applies. Do not post negative comments back at the negative comments. You can delete or block someone on your personal site. You can set a profanity filter also. Make sure you report any threats to you. Also, do not use all CAPS to respond to negative posts because that indicates that you are raising your voice at the receiver of your posts. That could make the situation worst. Post Positive.