Be persistent but polite with emails. Sometimes sellers take forever, especially the less professional ones.
A lot of Magic player are notoriously lazy.
It's only been a week so you could still be all right. Is the seller communicating at all? If they are communicating, that's a very positive sign. Most rippers won't respond once they take your money.
I ordered a couple Drains last year on ebay. Low feedback, but good percentage. The seller was very flaky, but I eventually got the product. Took 3-4 weeks.
Be mindful that you are limited in the amount of time you have to file a claim. I think it is capped at 90 days.