This sale seems very weird. It was seemingly sold by Roxy for Keys (although this sale is actually untraceable) to Adahn

https://backpack.tf/profiles/76561197993422884#!/compare/1770163200/1770336000

https://backpack.tf/profiles/76561198237193302#!/compare/1769817600/1770336000

Then it was seemingly listed on Marketplace by Adahn, then purchased back by Roxy through Marketplace?

You're going to have to contact either the seller or buyer in this case, because this seems to be a tradeback, which would be invalid to use.