At least in Germany (possibly also EU) when ordering something (excluding software, movies, food) online or via mail (i.e. not buying in a store) you have the right to send it back within two weeks without having to give a reason. This is to counteract the problem that you can try out a device in the store where you might buy it, but you cannot when ordering online. In any case, usage marks, like scratches, etc. just mean that you may not get a full refund.
Some retailers allow for longer periods; e.g. Amazon allows for a month instead of just two weeks.
This is off-topic, but the sensibility of EU provisions always amazes me. In other countries, it is pretty much up to the companies to offer such relief to the consumer as a response to competition, but there really is no such requirement, which makes monopolistic industries much worse.
Some retailers allow for longer periods; e.g. Amazon allows for a month instead of just two weeks.