Ok, well that shows that you bought a device at the upgrade price and you are keeping your existing data plan but not that you have unlimited data as your existing plan. Can you show us screen shots showing your data plan before and after you bought the DNA? You have to understand this is hard to believe given that other people have not been able to keep unlimited data when they upgraded on an unlimited data line.
Anyhow, if it is true it is like your upgrade didn't process properly, especially since the $30 upgrade fee has never been charged to your account, and you are very lucky. Although you say it reset your upgrade date to 20 months from now so that would indicate the upgrade did process. Perhaps there is a glitch in the bestbuy.com system? Worth trying if others have upgrades available and it wouldn't be the end of the world if they lose unlimited data. For me, I would hate to renew a non-unlimited data contract with VZW. They are too expensive unless you have unlimited unthrottled data.