Hello! If you load a save from Act I into Act II, it doesn't seem like you're allowed to access your clothing at all until you hit Act II. It just kind of disappears into the ether after you buy it (presumably because it's hiding out in your wardrobe, but you don't have access to that until Act II, so it's basically like it's not there). Sorry if this is a known issue/thing and I just missed it being talked about somewhere!