The "XX" with the "square" lens is actually called the XS, or X-squared.
One of the lenses may be ill fitting. This happens in a few cases where the original owner has changed the lenses (for reasons I outlined above).
If you live in the USA, I'd definitely recommend nose bridge tuning by @THE X-MAN or @zwc0442. Both offer outstanding "refinishing" services to customise your pair, at very reasonable prices. Unless you know what you're doing, it can be easy to damage your frames if you try by yourself without the right equipment and expertise. If you live in Europe, there are others who do it as well - List of Custom/Lens Cutting/Custom Frame Mod Contacts (cacatman)
I know you feel disappointed about your current pair, but don't beat yourself up about it. It takes time to learn what to look for, and what things are worth when you start collecting Oakleys. This page can help - Cacatman's Quick Links to X-Metal Information
Be prepared to probably spend more money than things are worth. Not many people here will take advantage of your (I assume) newbie status. I would recommend taking a look at this list of sellers in future - Which Sellers Do You Trust? Here's Cacatman's Top 27 "Best of the Best" O.F. SELLERS .
Just remember before asking a question to use the search button. Chances are, your question has probably already been answered somewhere on this forum.
All the best! And welcome!!
