Unreasonable repair cost and failing to acknowledge a factory fault

I bought a iPhone 7 in October 2017 at Greenstone mall. The sim card tray gave us problems when phone was opened in store by the assistant after the contract was concluded. I went home with the device and the tray was still a problem. I cracked the screen and took the device to be booked in for a repair. I stated to the sales consultant that she also state that the sim card tray has been giving me a problem since the date of purchase. The logistics company that expedites the whole process call me thia morning, to state that I have been qouted R6247,76 for a replacement device they won't be able to fix the phone due to multiple cracks. I enquire what if the sim card tray which is a fault on Apple's side. She does not give me a clear explanation and continues to assume that I have rejected the qoute instead of going back to the supplier to ask what of the sim card tray. Kindly assist because if R6247,76 for screen damage which I fully accept liability of is what I'm being quoted to replace the phone, this is downright ridiculous. Apple is also failing to accept thw fault on their side and are ripping customers off. I am only willing to pay the cost of repairing the screen and nothing more. I qas told that the device is covered under warranty for three months upin purchase. I bought the device on the 12th of October 2017.