Re your earlier question - Virgin mobile don't actually have their own mobile network, they are a "MVNO" (Mobile Virtual Network Operator) and actually use the network infrastructure of EE (originally it used the network of One2One, then it was swallowed up by T-mobile then merged with Orange to form EE).
I think the seller stating Virgin/Vodafone was mistakenly thinking Virgin (as a MVNO) used the Vodafone network, but it doesn't.