No option to exchange phone

I upgraded my contract a month ago and asked at every place I could about the camera and that I wanted to shot my children( fast moving objects) I wanted to upgrade from a samsung S6 and told them I wanted to take good pictures and I'm creative(movie maker etc) The person who helped me told me the Galaxy J7 pro would be good for me as I was asking for a cheaper option but still a very good phone. After a week I phoned them and begged to exchange the phone for a more expensive one as it did not meet my needs according to what they told me and I was also under the impression that I could return it if not satisfied with the phone before 7 days. (As vodacom has a 14 day return policy online -for not working, damaged of customer satisfactory). The manager of the shop kept on trying to tell me how good the phone is and that they can book it in to see if there is something wrong with it. I kept telling him there is nothing wrong with the phone and that its just not meeting my needs according to what I so clearly asked numerous times. Also I could not find a single Samsung J7 pro on display for me to play with in any store, not even Samsung stores. I think this is utterly bad service and surely the customer should also have the means to be heard if they are not happy with their purchase. In what way os the customer protected? No one told me that I cannot exchange it at all, only if damaged then only can I book it in for repair. Seeing as there were no J7 pro's for anyone to look at in ANY store( only a dummy and thats not the same) this would have been a great opportunity to have one in the store to show to people and habe a happy customer with a much more expensive contract and making more money off them in that way. I just phoned Vodacom and it will cost me a full R60020. 24 to buy out my contract, just to get a phone that meets my expectations. I think this was a bad move and they should really be more vigilant to tell people (that they KNOW is unsure of the quality of the phone) that they cannot in any way exchange the phone after opening it.