While regular bullying is a serious issue on its own, with threats, violence and demeanor of someone, you sometimes can physically flee away. Cyber bullying, while less on the physical side, cannot be fled from. Some people say that by just shutting your computer, phone or whatever device you may have down solves the issue, while in reality it does not. You will need your device some time soon either way.
Checking your mail, reading your texts, answering calls, all regular things, but if you are the subject of cyber-bullying, any of these actions will be met with violent messaging, people telling you to kill yourself, people that threaten you, people that mock you. If you are subject to cyber-bullying, your mailbox may be full of those foul messages, your Facebook or other social medium you use floods with threats, but that's not even the worst part. This person reaches beyond just you. They tell lies to your friends, make you evil to strangers, they make being online an unsafe place to be.
But sometimes, things get even worse. Sometimes, people get calls from those people, texts, they're being stalked. Or worse. The bullied person suddenly gets their door kicked in by the police, because they had received some form of terrorist threat, while in fact the bullies made this up. Usually, the person who gets their door kicked in is streaming, making a live show for thousands of people to see.
And the people that bully others online think it's all just a joke. They usually do not know that they are attacking actual people, they do not know they are destroying them mentally, because "it's all just a joke."
70 years ago, our great grandparents watched people die infront of their own eyes, dodged bombs as they saw their lives flash before their eyes, lived In poverty and got pointed at by the rich, got beaten and insulted by their parents, lived through decades of PTSD and trauma, worked sweat and bone in crappy jobs to be the great people they were. They took insults from the government during the counterculture of the 60s, they got insulted by so many people and managed to overcome it like true men and women.
And yet today, some kid has to go to therapy because someone on the internet called him 'meanie' saying he got PTSD from it and made a whole television advertisement about it.
TLDR; Suck it up and toughen up. Life's hard.