your in luck, i actually own this t-shirt in white and blue, which i bought from selfridges so its the real thing, the paint effect shouldn't really feel much different to the cotton, obviously alittle different, but not much
the best place to run the sizes from are the Alexander McQueen site as they are available on the online store for the US and UK :
Here
from the pictures on ebay its difficult to tell if they are fake, but also looking at the images there is one thing missing from the tags, there is usually a clear bag attached to the tag (tha same size as the tag) and its missing, and ebay aren't the best reputable place to buy designer clothing and accessories, and for him to offer an exchange is kind of fishy, like as you said they have all sold out, they pretty much sold out in a couple of days here
the best thing to do is probably return them if your not satisfied with them
i hope this kind of helps
