First try to contact the author: http://themeforest.net/item/flatads-classified-adswordpress-theme/7157644/support. If they can’t help, you can contact Envato. If you can show that there theme isn’t working as described and that you contacted the author, they’ll usually give you a refund. Good luck!
This FAQ should help clarify your questions: http://themeforest.net/licenses/faq#item-packs-a. Essentially, each item in the pack has it’s own regular license. So you couldn’t use the same PSD for 2 different clients, you could use each of the 100 for 100 different clients.
Most people just don’t need the extended, especially when it comes to websites. Here’s the detailed FAQ for when you do and don’t: http://themeforest.net/licenses/faq#faq-section-regular-and-extended-licenses.
Looks like your Codepen is a dead link.
5-star ratings are a key part of sales. You don’t have many ratings yet, but that’s a great ratio. If you keep getting ratings, your sales will go up on this item and future items as well.
Yep. Offering one is a perk, but it’s not required.
Nope, it’s just me. I’ve just been an author a very, very long time.
Edit: Oops, wrong account.
. . . riding a weasel, riding a woodpecker.
As of about 1 year ago, it was impossible to transfer ownership. The only way was to remove the item and reupload, but there are rules restricting that as well (to prevent manipulation of homepage exposure). I would suggest submitting a support ticket.