If you use Paypal you can claim your money
how to recover INVESTED BITCOINS to scam sites ?
That's what's good about Bitcoin (not that good in your case) , it's impossible to make a chargeback unless you didn't use fees on the transaction then the BTC should go back to you after few days , however most of websites and individuals only accept confirmed Bitcoin transactions .
there are hundreds of websites offering btc investment
new users got scammed everyday , HOW to prevent this ?
Honestly I never got scammed by this kind of website because I use simply my brain . Like there isn't free money , there isn't free Bitcoin .
Scams are too obviously and they are most of the time "too good to be true" , (E.g deposit 0.1 BTC , receive 0.2 BTC) .