Why didn't you used escrow service for this deal?
Please do not take it other way, because the lesson you have learned it was necessary.
Lesson price $400 for the mistake of not using escrow. I hope you will not forget this lesson, ever.

I checked the DHL tracking number. It says "Shipment information received". So the parcel has not been picked yet.
I think DHL will pick up the parcel soon and then they will update the tracking info.
Otherwise they wouldn't updated that the "Shipment information received".

Wait sometime or you can call DHL again to confirm when they will pick the parcel.

And by this time inform the seller about this thread. So that he can say the story of his end.