Diamond Wireless - Failure to recognize trade-up credit

[mah347]

I went to Diamond Wireless, a "Premium" retailer for Verizon Wireless (1046 N Colony Rd, Wallingford, Connecticut, 06492 Phone:860-266-8119) to upgrade my wife's iPhone 4 and my iPhone 4S to the iPhone 6.  My wife and I were told we'd each receive a $200 VISA gift card for the upgrade and placed our order, one 16GB iPhone 6 and one 64GB iPhone 6.  The phones were on backorder and arrived 10/22.  My wife and I went to the vendor on 10/26 to complete the transaction.  I asked to confirm the $400 in total trade-in credits but was given a run around.  I was told that Verizon Wireless changed the method for which the evaluation is made and the phones had to be upgraded online for the promo.  This wasn't communicated by the vendor prior to this time.  Needless to say, they wouldn't offer the same deal and seeing that 10/15 has passed, no one will.  I imagine that Diamond Wireless is to blame for this as they failed to communicate the method in which this deal was to be honored.  As a long time customer of Verizon Wireless, I'd like to see Verizon step up for their customer and honor the deal and correct the mistake of their partner, Diamond Wireless.  I don't find this acceptable and it's tough to determine who is to blame.  I think Diamond Wireless but they point the finger at Verizon.  Please let me know my options.  I'd like to be viewed as a valued customer and see Verizon step up to the plate to do what's right.  I look forward to your response.  Thank you.