Broken phone that was only used for 6days...

I bought a phone on the 12 of May 2020 at Goldenwalk mall because I was working that side...The phone broke on the 19 May 2020 and I took it to trade route mall totalsports because they are the same group... when I got there a guy by the name of Xolani was helping me first he said he will book this phone and I asked him how is that possible because it's still under the 7 days guarantee he didn't even look at the slip I had....the next thing he said he wanted the charger which I was will to go fetch as I was on my way he called me saying he can't exchange for me because it was bought at goldenwalk mall and I need to return it there...how is that possible because I stay near trade route and their store is the nearest to me...and I would have not bought the phone in their group if I heard known that if I have a problem I will be required to go back to Germiston In the mean time they have stores near me and the phone was bought for educational purposes so now I'm stuck with this problem....and my daughter will not be able to get her work done and the phone just stopped working while she was busy with her school work...That also means they sold me a phone with manufacturer problem coz it only worked for 6 days only and it died and now it's my problem ...because Xolani can't help me...