****med on upgrades

Done 3 upgrades over the phone. The 2 small contracts for the kids was no problem except for the vouchers that we are still waiting for.. The last one is a Red plus contract. I wanted the LG Velvet with the dual screen as advertised on a lower priced contract. The person that helped my wife confirmed that it is available with the red contract. Now we are told that the dual screen is not available on this deal. How can a lower contact qualify for this deal but a higher contract cannot? Atleast this contract is coming to an end. 20 years with Vodacom and this is the thanks we get.