Paying for a faulty product without resolve

On the 13th of November I upgraded to the new samsung galaxy J7 Pro, at the time I was on 2 weeks leave and the phone was working fine. As soon as I returned to work in a private game reserve close to kruger national park, I had no signal. I work 6 week cycles which make it impossible just to leave and drive 250km just to take them a faulty phone. After managing to arrange for someone to drop the phone in Nelspruit on the 30/11/17, they tested it and said nothing is wrong with it. They put a whole new motherboard in, just in case (yet nothing was wrong with it). They then couriered it back to me which is almost an impossibility as no courier companies are allowed into the private game reserve, again managed to arrange for someone to collect it for me. And by no surprise at all there is still no signal. Now I have been notified that the phone has to be sent to Johannesburg and if I am lucky enough for them to provide a credit for me on a faulty phone I was given. I may not change the contract, but I may be able to pick another phone that hopefully works and pay in a difference of who knows how much........all while still paying for I phone I don't have because it doesn't work. Since we are basically in the middle of December I assume I wont have this issue resolved till mid January ( if I am lucky) and thus paying for 2 or 3 months of new phone usage, while I don't have the phone.