Please replace the unit

I bought a mobile phone from Foschini in March within the weeks the phone was giving problems, intermittently started with charging error about foreign substances, thought the phone is not wet or moist, it wont charge till such time it will charge, then came the Overheating when using apps and have to restart the phone this happened for sometime, since I am staying in the rural area I had to wait till was back in town, the day I took it back it was complaining about overheating then the gentleman at store who was assisting confirmed that the unit was hot , because I did not have all the necessary things to leave it, I had to comeback the next day, it was booked in for checking up, it took a full month from 15 April to 15 May to get it back, the report was that the repairer could not find anything wrong with it, only did software update (the whole month sitting there) collected it and the next day it did the same thing overheating whilst using it at church, on PDF and Bible App, did factory reset and that did not help. before I could go to the store , the store called me to check if the unit was Ok and I explained what was happening, to my surprise I was asked to take it back to the same repairer that kept it for a month for them to check it again, and I refused because I did not understand what help do they have now, so I was called asked to factory reset the unit by the same repairer and explained to the store rep, I was then called again being told that the store manager is asking for it to be sent to Johannesburg for repairs at the supplier and my point is again I am going to be without a mobile for a period that is not know, have been inconvinienced already to be with a unit for month whilst paying for, I feel like i am not being taken serious and paying for defective unit, why cant it be replaced and they deal with whatever hardware issues that it has. I am still waiting for a call to hear what I must do now after I made it clear that its unfair for me to be paying for a phone that I am having issues with and not getting loan unit again when its being taken away for repairs. I am not happy at all with this treatment. Is this a race issue or I must not go there. Its unfair to feel like paying full price for a secondhand unit.