Hey there! Here comes a little review about the online shop 'Kpopplus'. They also have an ebay shop (I can't really remember, but I think I ordered from there once). It was my first time ordering from their actual site. The site looks really nice and neat. They sell a lot of stuff – next to CDs, DVDs and Kpop Merchandise they also sell cosmetic products, wigs and circle lenses - even Chanyeol's jumpsuit he wore in Exo's Showtime...
I preordered B.A.P's first full length album 'First Sensibility' with an unfolded poster on 31.01.2014 and payed with Paypal. They sent me an e-mail, confirming my order, with the invoice as a PDF file. If you ordered there and didn't receive an e-mail, check your spam folder! All of their e-mails ended up in there.
The album release was on the 3rd of January and they sent me an email the day after to confirm the shipment, so that was quite quick! Also Kpopplus provide a tracking number to check the status of your order and there you can also see all the details and download the invoice file again.
I can't really say anything about the customer service since everything went smoothly and I didn't have to contact them about any issues.
The shop was down for several times, they probably had some provider issues.
As for the prices I am really pleased: I took a quick look at other CDs and overall it seemed really cheap compared to other online shops (e.g. yesasia).
The shipping costs can be both good and bad. First of all, they do ship worldwide which is already a plus. The shipping costs depend on how much your package weighs, though. Since I only ordered one CD they were about ~6-7$ which is really good compared to yesasia's shipping costs. However, when you want to order more than one CD or something that costs more than 16$, the shipping costs will increase which will make it very expensive. Additionally, they don't offer free shipping costs over a certain price limit, so I'd recommend this site if you want to order only one CD that isn't too expensive.