Listing incompatible Hardware as options when purchasing laptops online.

Is it common practice for Dell to sell computers with incompatible hardware listed as an option while selecting parts?

I bought a laptop from you and later found out that my laptop doesn't have an antenna for Wireless-N built in; I was basically robbed of the money I spent to upgrade the card to ABGN from the ABG during ordering of my Inspiron E1705.

I've contacted your customer service and had a customer service manager hang up on me when I told him that it was a deceptive business practice (your tech support manager was on the line to hear that). I have reference numbers, my service tag, and all other relevant information available upon request.

I just want to know if anyone actually cares enough to help me before I bother with all of that; I was told that even though the sales tech didn't catch the mistake during the order confirmation that after 21 days from the purchase date I'm out of luck.