If you want to get the 7160 it has the same capacity as the one you have but has SATA, there should be no charge, but if you want to upgrade to the 7232 that has the 500gb drive, there is a $40 charge. If all they have is the 7232, they may wave the charge, but not likely. Contact a Verizon store near you if you have one. You may drive to the store and do a same day swap/ I think they are closed at 5pm est. But if you are out West?
If not, contact Verizon and explain your issue. The 6xxx also does not support the full HD graphics for the guide. Tech support may help, they are open on the weekends and may be able to place the order for you.