I want another phone not the one I got

I bought a contract phone yesterday at mtn Northgate shopping center and the person who sold this contract phone to me didn't explain a **** to me about the phone. She seemed like a learner and very lazy to do anything. I got to find out about everything when I got home that the phone doesn't have playstore and many features that I need when working from home. Have playstore and many features that I need when working from home. A lot of apps are not operating on this phone and I am not happy at all. I then went back to mtn in the morning to exchange cos I don't want this phone anymore. It's useless for me and it's not what I asked for and they told me they can't help me like hello people I will pay for this stupid contract. I do not want this phone full stop and can't stuck with it for two years. I will keep escalating the matter until they give me what I want cos I bought it yesterday and it's not like I want to cancel the contract but to swap phones.