Bad service Mr Pricemobile

Bought a phone after 3its was slow and freezing, called the store and was advised to update the software. After few days o took the phone back to the store at about because it was just not working for me. And I was told I should have brought it back within seven days. The consultant said he will book it for repairs. I refused and asked that I be given a better phone that will be reliable and I would not mind adding the money as long as I will get value or a good phone. The consultant refused me that and refused when I asked to speak to the manager. I ended up leaving the phone him since what I was asking was not making sense and he only wanted me to take what he said. Mind you the very consultant is the one that insisted I take the phone even when I had my doubts about it . I am still not sure how to approach this. I'm disappointed and frustrated...just try be calm.