For the cyber-bullying end of things- no, hasn't happened. I didn't have regular access to the internet for most of my formative years, & it was before social media anyway. Even now, I barely use social media sites to begin with, so the opportunity for it is minimal.
The thing about cyber-bullying is, it largely relies on two factors: anonymity & the victim's participation. It's not super hard to block someone from accessing most websites these days if you talk to the right people (assuming you don't have the ability yourself), so it's usually pretty easy to make a cyber bully go away by tattling. At least, that's what it seems like- I know I'd insta-block someone who crossed a line without a second thought.
Anything is hackable these days. If somebody really wanted to, they can get your information. Even if it’s just a simple email address used to sign up on a video game collectors forum.
For the hacking end of things: the above is very true, but the question becomes
why. Why hack one person specifically, especially without a financial, political, or social gain from it? There's really only one reason- that person made themselves super easy to hack by throwing valuable data out into the world for anyone to find. The VAST majority of people aren't doing that.
The vast majority of hacking victims weren't targeted at all. Most hacks start off as data fishing- the culprits throw a large net out there, full of bait in the form of 'your computer is infected' pop-ups they snuck into the code of a large website, malicious code stuck into beign-seeming downloads, and mass emails using computer-filled forms from data stolen from larger targets. Only the ones who take the bait & give more data are usually targeted. What that means for the everyday person is simple: be careful what sites you go to, don't download unvetted files (even from friends or family), be suspicious of weird emails, & monitor your accounts... after all, even if you're doing a good job, someone who has your data could make a mistake & get you hacked as a result. Somebody got my bank account info once, my fiance's was compromised a week later... thing is, there was no commonality in our banking/shopping at the time- save for the actual bank we use. They got hacked, we had to clean up the mess. Luckily it went well & nothing was lost.
Why am I so sure most hacking isn't targeted attacks? Pretty simple- I'm a girl. That sounds utterly unimportant, but as someone who's online habits are gaming-centric, and that's traditionally a male hobby, it's often really, REALLY obvious when something is trying to sound targeted & just isn't (No, I'm not the cute guy you met in the chat room last night). I once got an email claiming to have hacked my computer, & that I'd need to send blackmail money to protect myself, with my password in the subject line. Two problems: one, the password was years-obsolete and never used on that email. Two, the 'blackmail' was for a hacked webcam video of me jacking off to a porn site. Well, that would require me to both have a penis & visit porn sites, wouldn't it? I marked the email as a scam & went about my merry way, not hearing from them again. Honestly, it's impressive how wrong they get things sometimes.