The legal environment has improved immensely for European consumers during the last few decades. Mostly this has happened through EU-legislation so that similar rights are in place for consumers throughout the EEA. Most of these have been implemented into Icelandic law. You can find more details on individual legislative acts on this website, for instance the directive on package travel and mobile roaming regulation, the regulation on air passenger rights, the directive on distance selling, the unfair commercial practices directive and the sale of goods and associated guarantees directive.
Before making purchases from a trader based in another European country it is important for consumers to familiarize themselves with the rules that apply. You can turn to your ECC for information and advice, but you can also find extensive information on the ECCs websites. It might also be useful to look at some of the brochures from ECC-Iceland or reports from the ECC-Net.