I have been using Paypal for over 6 years and never had a problem with them. If you are having problems, it is most likely that you have an insecure password, or logged into one of the phishing scams websites and entered your info for them.
If a buyer complains, and the product you sent them was not what you promised then I guess that’s between you, the buyer, and Paypal/Ebay. I have sold dozens of things, and bought more than that and never had a single bad transaction.
It’s a lot safer than the freebie world, if you are careful and only deal with people that have a proven track record you will be fine. Paypal is about the most reliable way to safely exchange money online in my opinion.