There are a plethora of illegal books, many run by college students, young adults and even teens. How secure are these websites??
What I am really asking is how easy (possible) would it be to hack the site and change a users balance without being detected??
There are ways to avoid such questions in the future and not put yourself into lots of related questions.
Just stick with famous and reputable bookies from now on. It might not be an assurance that you are 100% safe even using famous bookies but at least you will minimize the chance of being scammed by these sites as they are registered and centralized.
I wondered why there are users who still end up in illegal bookies despite several famous bookies today.