According to PayPal's UA a seller is only protected under the Seller's Protection Policy if two things happen:
1) The seller ships out any merchandise within 30 days of receipt of payment in full. Personally I think a window of a month is ludicrous but that is there policy as stated in the UA.
2) A seller must ship via an online trackable method whether that be FedEx, UPS, DHL, whatever which comes with online tracking as a default or if you choose to use the USPS then Delivery Confirmation, Signature Confirmation, or a similar method of providing proof that the package reached its intended destination.
If you cannot provide proof of both to PayPal when a buyer disputes receipt of paid for merchandise then you might be screwed //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif