The buyer paid for Parcel Select Ground, not for the flat rate envelope.
As noted in the other post, eBay has decided to phase out access to Parcel Select Ground labels, even though USPS has made no changes in their services or policies, and it's offered by all other online postage sellers including PayPal, endicia, stamps.com, etc. When it's not offered, the shipping label page usually defaults to the first option on the list, which is the Priority Mail flat rate envelope. You can purchase Parcel Select Ground postage through PayPal at
www.PayPal.com/shipnow
But do compare prices before you do that. For Zones 1 - 4, the USPS online price for Priority Mail is less than a dollar more than Parcel Select Ground. The shipping section of the listing shows the retail price for Priority Mail, so the price difference is exaggerated. If you're a TRS you get a 3% discount when purchasing Priority labels through eBay, which often makes it cheaper than Parcel Select. And of course ground shipping is slow and is much more likely to result in damage to fragile items.
IMHO Parcel Select ground should only be offered when necessary such as for hazmat or Oversize packages (i.e., length-plus-girth above the Priority limit of 108 inches).
