From my expereince I wouldn't even bother trying to contact four marketing - they don't care about their customers therefore they don't care about their brands reputation!
Check this thread out :
http://kitmeout.com/fashion_talk/viewtopic.php?t=1036
Can you post some pics or give us the ebay item number so we can view it if its still on ebay's system?
Does it have the Sportswear Company Spa label?
The jacket I got had a label in it saying about it only being manufatured in ??? (can't remember) but the testing, development, designing, styling, etc was all still done in Italy.
What is the fabric (% mix?)?
What is the Stone Island label like on the neck? Does it have an embroidered number or a die cut number?
What about the badge & buttons? - compare with your other ones.
Look at the seams & how they are sewn -again compare with your others.
Hope this gives you some pointers to look at - but best thing is to post pics or give us the ebay number so we can look at the listing.