Billing Problem that can't seemed to be resolved by anyone

Question

So I started a family plan with Verizon about 2 weeks ago. We got a two iPhone 5s ($550) and a single iPhone6($650), price per the Verizon website. We got charged for the equivalent of 2 iPhone6 and 1 iPhone5, $100 overcharged. I called Verizon to get this problem resolved, they informed me that since I started my plan through a retailer, I need to go to a Verizon store to resolve my problem. I went to the Verizon store, they agreed my bill was incorrect, but told me they weren't able to change it because I started the plan through a retailer who wasn't a Verizon store. I call Verizon back, tell them what the Verizon brick and mortar store told me, and they told me they aren't able to correct it, and that I should contact the store directly.
I call the store where I started the plan, the customer rep remembered me and I told him my problem, he said it must have been a mistake, and that he'd look into the problem for me. 3 days later, no call back, I call them. I get the store manager, who tells me that the billing was correct, that they charged me less for one and more for the other to balance the cost. WHAT?! Now I understand that retail stores can jack up the prices of the phones and the cost might not be the same as advertised on the Verizon website, but the sales rep admitted the mistake, and the way the manager explained the inconsistent bill simply makes no sense. The sales rep admitted he made a mistake, the manager wouldn't correct the bill. She offered me $100 store credit to offset the difference. Useless, I did the deal in LA, but live in San Diego.
Seems like no one can/want to help me, a mistake was made but I'm paying for it.  

Answer 1

This is entirely with the store you bought it from.  Go to the corporate office customer relations for that company.   I have to agree with Verizon here, there is not much they can do.