PayPal provides you with a PayPal account and not a real merchant account. Your money is deposited into a PayPal account, which PayPal controls, rather than your own bank account. If PayPal even wonders for a second about the validity of a transaction, they can freeze your PayPal account immediately. They can even pull your money directly out of your personal bank account, many times without even a phone call or email.
If you think PayPal treated you unfairly and want to dispute their decision, you will be at their mercy as PayPal plays the role of the investigator, judge, jury and executioner in all issues regarding your account. (You agreed to all of this, when you signed up.)
Sound fair? Well it's not!
Explaining your version of what happened, in most cases seems to make no difference. They will refuse to provide you with their "detailed information" from their "investigation" and will not disclose documents they apparently relied upon to make their decisions.
PayPal won't do that to me!
Are you sure? After all, there are thousands of detailed horror stories posted all over the web about people being robbed, abused, unfairly treated, lied to and scammed by PayPal. If you don't believe it, Just search Google.com. You'll discover thousands of businesses and individuals that were ruined by PayPal (and these are only the ones that decided to post their stories online.)