Talk to your child, make sure they are OK, and make sure they know you are on their side. Some children can be embarrassed or ashamed of the situation they might find themselves in. It is important to have an open dialogue with them to ensure their cyber safety. You can follow these Cyber safety tips for parents.
Next, if the offenses are serious enough, you should consider contacting your child’s school and/or your local law enforcement agency. Just because it happens online, you should not take these offenses lightly. Also, be sure to NOT erase any traces of what you find online as these traces (e.g. comments, messages, photos, etc.) can help in taking action against a cyber bully.
Finally, contact the web site(s), social networks, or mobile phone providers that might have been used as a platform for these offenses. They most often take these offenses seriously and are willing to help stop and prevent these behaviors.