Your info is a bit confusing. If you bought an unlocked phone, that said it was originally Verizon, then you bought a CDMA phone. They didn't send you anything wrong or a wrong version. You can contact them about returning the phone and getting your money back. Then you can locate and purchase a GSM phone if that is what you are looking for.
You can't 'demand' someone send you a different kind of network phone. The advertised phone would say what network it works on. So unless they 'said' that it works on the network you wanted, they sent you what they advertised.
Otherwise you would have to keep the phone and change to a carrier that uses a CDMA network.