AT&T locations in Las Vegas, NV

I walk in the store with the intention to buy a new iPhone as I was eligible for an upgrade. I was told that I was not eligible and that I had given up my rights when I received a discount for the service. A girl named Lynda or something, a tall skinny girl with brown eyes and dark hair and wearing glasses, kept trying to sell me on a new plan, and told me that ATT no longer does the free upgrades, and that no matter what I have to pay full retail price one way or another. I left the store to shop around, and I was able to switch to Verizon where I got an iPhone 5C for $99.99 and was added to a family shared plan for only $25.00 a month.
I then call customer service to confirm that I was not eligible for an upgrade. They told me the store completely made up a lie in order to get new contracts and/or commission and that I was eligible for the same service I got at Verizon. I call the store back very upset and told the manager what happened, and he literally says OK AND HANG UP ON ME. No apologies! no explanations! just hang up on me. I feel disrespected and lied to and I wanna make sure that everyone knows my experience with this store, so that you are not lied to or talked into spending money you do not need to spend.
The management and this girl need to be fired!! I will make sure to tell anyone I can about this to make people aware!!