Refurbished or New iPhone 6s?

Apple will in almost all cases replace an under warranty iPhone with a refurbished unit. Also it's very unlikely they send the iPhone back to the U.S, since their would be no matching iPhones for Dutch carriers in the U.S. They more than likely sent it to the Dutch Apple representative, and had it replaced there with a model for your carrier.

You may not be o.k with it, but it's their warranty policy.

Refurbished units will come in a non-descript box as you describe.

If there is still an issue with the replacement, it carries the remainder of the warranty on the replaced unit or 90 days whichever is longer.

So you need to return to your carrier and have them take a look at the replacement iPhone, and have it replaced again if necessary.

Replacement iPhones will come in a brown box. And As was said will have whatever warranty time was left on the original phone that was replaced or 90 days whichever is longer.

As long as you continue to be under warranty there is no limit on the replacements. You can replace it as many times as is necessary during the warranty period.

I am in the US and warranties vary by country. However replacement phones in the US can be new or refurbished at Apple's discretion, that is the warranty here. I would not worry about refurbished devices as they are thoroughly tested. I would worry about your defective pixels and would get that taken care of, likely another replacement. Your warranty status above says Oct 27, 2016 so you should be covered.

Hi Hod, the packaging does not affect the warranty. New ones come in the white boxes, replacements come with no accessories in a brown box. There is no limit to the times the phone can be replaced if they continue to be defective but this is unlikely. I had one iPhone replaced for a bad wifi chip, the replacement lasted one day due to a faulty display, took it back and got a third one, still working well after 2 years...