Disappointed

I went to MTN FESTIVAL MALL, looking for a new phone as I work for Takealot/Mr D I came with a specifications so they can give me a right phone and Akshay Harrissunker up selled me OPPO phone. I went to work and the phone don't work for my App I then came back the following day to explain to them but no one is willing to help me and the Admin manager said they can't take it back . I then left the phone a the shop , no one called me since then.. I went back after 3 days and found the Manager and he said ... he is still waiting for regional manager to update them what to do and he promised that he will call me back but still today no phone call from him. I am very disappointed with MTN I don't think I will ever use them again they don't know how to treat their customers.