That isn't true what Tradesy said. The seller has 3 days to confirm and 10 days to ship. I know because this happened to me recently. Kind of. I never received the bag that I bought though. The seller confirmed immediately and we even talked about what would come with the bag and she EVEN told me she was shipping the next day! 7 days later I still never got a shipping notification or the bag and I reached out to the seller several times and never heard back. I told Tradesy around the 8th day and they said they need to make sure it hasn't shipped first and reach out to the seller themselves. They even told me their policy is 10 days before you can cancel a sale that hasn't shipped. They never heard from her and I got my money back at the end of the 10th day. I was pissed at the seller though.
Something went wrong with your scenario unfortunately. Probably some new guy who didn't know what he was doing. That's scary and I feel for you. I hope they make it right because they caused the problem, not you. You were still within the time frame. But just as my opinion, as a buyer, 10 days is a long time to wait for a bag to ship that you are excited about. If it's more than 4, I'm reaching out to everyone asking when they will ship.
I think it's evil the girl got the bag and it was not kind enough to mention it to someone. I hope she sleeps good at night. Karma will get her one way or another.