I used 7dayshop.com fairly regularly in the past to purchase memory and the occasional camera, and most of the time it went without a hitch.
I’m waiting on a camera from them at the moment too but it was ordered before I knew the following: they ship US sourced products with US warranties! Reviews are mixed with some people having good experiences and others bad.
If you do find yourself without cause to complain about an online store what can you do? If you live in the EU there are laws regarding distance selling (UK version).
When you receive the goods you have a 7 working day cooling off period during which you can send the items back to the retailer without giving a reason. This is akin to browsing in a shop and not buying. You may have to pay the postage to return the goods however.
7dayshop, in their camera policies page do state that they’ll pay the postage if a manufacturing defect is found within 7 days or less.
If you have the item for more than 7 days you must contact them via their support page. It’s not clear whether they’ll have the item repaired/replaced or not, and later on they say, “If the item was purchased more than 1-year ago, then the warranty period is up, and you must contact the manufacturer directly – not us – to arrange for a repair to be made at your expense.”
But if the warranty wasn’t valid in the first place…
The Oasis.ie page on consumer affairs has links to more information that should broadly apply across the EU.