Clearly I have no idea what the warranty arrangements for Fiat are in Greece, but I'm guessing that if the suspension failed on a 500 during the 3rd year warranty phase, Fiat would cough up. I only say that because if they are prepared to replace door handles and the entire boot handle incorporating micro switch and of course electric steering motors as was done on our old POP during year three, then replacing shocks/springs etc, should be a given.
My issue particularly with the shock replacement, is the fact I believe some owners have had just one failed shock replaced, which is utterly nuts because they should always be replaced in pairs, same with coil springs. If a dealer told me they were only going to replace one shock, I'd tell 'em where to shove it and do the job myself and replace them as a pair.