You write "100-percent satisfaction guaranteed or your money back!" While this is certainly an effective and admirable policy to uphold, helping to ease a customer's potential anxiety about purchasing in a virtual setting, it sometimes brings a potentially detrimental effect: It presents an open door for fickle shoppers, and even abusive scammers.
This is a really good article with some really good sound advice but................
If you accept PayPal as payment, then you might as well have a "100-percent satisfaction guaranteed or your money back!" return policy because this is basically PalPal's policy and their policy trumps your policy if you accept PayPal as payment and your customer opens a buyer dispute case with PayPal as PayPal sides in favor of the buyer in nearly all cases.