Got charged full price for an upgrade

On September 12th I pre-ordered my iphone6 like so many others, a few days later I get an email, that there was an issue with the address provided.  After calling and spending over two hours on the phone, I get a representative to assist.  DESPITE repeating this is for an upgrade and all we are doing is updating an address for payment(no idea why this needed to be done), the representative charged my credit card full cost of the phone.  This is a $500 difference from the price I should've been charged.  Countless hours on the phone with customer service I finally get a representative that understood the error and put in an escalation ticket.  I was told to expect a call in 24-hours, which ofcourse never happened.  So again, countless hours on hold I call and get shuffled through several reps that have no idea how to assist me, finally one does and can see the ticket escalation and tells me, to call back in a week to ensure the refund was submitted properly.  A week later(today) I call, and again go through countless reps whom don't bother to read the notes properly even though I offered the escalation ticket number.  I'm currently going on 84 minutes on hold just to reach someone.  This is unacceptable, I've been a customer for many years and I'm at the mercy of a representatives lack of attention to detail. I am beyond fustrated and disgusted with the lack of efficiency and training for representatives.