I empathise with the social awkwardness. I'm 19 and also painfully shy, however I have recently become much more pushy when it comes to dealing with messy situations in which you have to press to get what you want. The key thing to remember is that you are the customer and they are at fault. Also, try not to care what they think of you.
I would explain that the cage simply is not suitable. You were advised (falsely) by a P@H member of staff that it was suitable, and therefore feel that the responsibility for the mistake in you buying it lies with P@H. They misled you and, as such, they should refund you.
I had the Alaska, because it has a lovely big front opening door. The only problem, is that it is quite flimsy and not made of very high quality materials. If you want to lift the top off, all the panels often come apart, the clips attaching it to the base pop off and the top section must be rebuilt.
I too liked cages such as the Alexander, but their tiny doors were enough of an issue for me that I did not buy one. I found my near perfect cage in the Savic Hamste Plaza. It is more expensive than the Alexander or Alaska, but it has a big front opening door and us a very high quality cage.
You can see my review of it here:
http://www.hamstercentral.com/commun...ter-plaza.html