Yes, it's possible. We all get sloppy from time to time.
Still it has only been four days since payment. Even if shipped, it won't arrive before August fifth.
If the seller continues to ignore you, while you do have 45 days to open a case, I would do it sooner.
If only to make him pay attention.
Maybe 20 days-- that's August nineth.
Do not close an Open Dispute until you have the item and have inspected it. You can't open it again.