The Cyber Helpline is an award winning, not for profit organisation who will help anyone over the age of 13 who has experienced online harm, including stalking, harassment, revenge porn, blackmail, account hacking and many other online issues. They can talk you through your concerns, give you advice on how to manage unwanted contact, secure evidence and also how to make sure your online activity is as secure as possible. The Get Help section of their website sets out how to get in touch with them.