URGENT - Vodacom representative/s NOT focussed on client requests - rather on sales volumes

Last week Friday I went to the Voda shop in Somerset Mall to enquire about an "upgrade" on my fiancee's contract (I pay the account). I emphatically and explicitly informed them I was interested in an upgrade for approximately the same monthly fee I currently pay. They showed me various phones and eventually pointed out that the Huawei Nova8i would be a good phone to use. We finished the paperwork and left the mall. Apart from the problems, my fiancée is having with the phone (no google play store, etc,) I found out today that the "upgrade" is going to cost me more than R500 per month! This is NOT what I wanted and agreed to with the Vodacom shop representative in-store. Vodacom made a serious mistake and needs to cancel this "agreement" immediately. I will sign a fresh agreement and will accept nothing less than what we discussed and verbally agreed to in-store. I cannot believe that the Vodacom representative could have made such a serious mistake. It leaves much to be desired in terms of "listening skills" and providing excellent "client service".