Got a MacBook that doesn’t work plus poor service upon return of the device

I bought a MacBook online I tried to return it to the same store I bought it from and they said there is nothing they can do I should rather resell the Mac back with alarmist half the price as I got it. I bought for R4999 and they want to give me R2750, how absurd is this? They do not even attempt to get clarity on what should happen from their manager or regional offices. I’m angry, nothing they say is sound. My order number is 862421 I’m still in store and tried calling the numbers for regional offices unfortunately I couldn’t get reach of them. Cash crusaders should continue buying and selling stuff that doesn’t work, really it should!