A few people have been scammed on the site, Only use paypal to pay for items for sale by other members. If they will not use paypal, its likely a scam NEVER SEND E-TRANSFERS OF ANY KIND.
I can't really tell but it doesn't look like you had to use any supports. Did you? I have some small Fieldsheer bags I want to use on my NC700. I didn't think of putting the strap under the seat, thanks for the idea.