That's what happens when you are a new PayPal account. They hold your funds for about a week before you can withdraw them. He's probably got a stolen account anyway. I had a similar thing a few weeks ago from another seller (probably the same guy under another name). I sent him PayPal and he disappeared off the face of the earth. Fortunately PayPal held his funds and sent my money back.
Bottom line is, what the hell do you expect from a place like this? 100% of the Starbucks sellers get their cards from questionable (and this us putting it gently) sources and most of the cards eventually get zeroed out if you don't use them quickly. Escrow is meaninglless because while it might take 3 hours, 3 days or 3 months but SB does catch up with them and they can track the numbers no matter how many cards you move them to and eventually will close the card if you don't spend it quickly before they catch up. I had one unused card zeroed after almost 3 months. That one came from eBay. Look what happened to the seller (SBDEALER I think) who posted all over how his cards will never get zeroed because he was so special.
He sold a few that were OK and all of a sudden people are reporting their cards were shut down. Now he locked his thread and probably disappeared leaving users stuck all over the place. Maybe he will be back but the point is EVERY Starbucks card is questionable no matter who the source is.
Put in a dispute with PayPal. They will hold the funds until the problem is resolved or return your money. That's why they hold the funds from new sellers for a period of time.
Good luck.