Coordinated Transfers
This option is designed for a more open delivery in which the Seller and Buyer will need to work together to complete the transaction.
If you go to the item you like you need to look at the Delivery Method and see if it said Coordinated Transfers.
Example
This user kind of had the same issues as you and they found a seller and got items from them.
(Please click and read this post to fully understand what I meant. I’m not sure what steam items you’re looking for so this Seller may be no good for you.)
Lucy 