Not geting what I paid for

My problems with the contract I have with Telkom is endless. The contract for the iPhone 5S was taken out in February 2017, the device started to give me problems in March 2017 till today. The device has been taken to the iStore twice, nothing was done because apparently no fault was found. This is surprising as I have been sitting with the device that barely worked and I have never enjoyed the use of this. This I find to be unacceptable because I am paying for a contract which I am not benefiting from. Eventually I decided to take the device to Telkom directly, bearing in mind that the 12 month warranty is still active, and I receive an SMS telling me that this device is now out of warranty and I need to pay more than R5000 to have this repaired, utter nonsense!!! This device needs to be replaced as I have given the service provider enough opportunity to "repair" the device. I have been seriously inconvenienced, I had to borrow a phone, get another SIM card and spend extra money on data and airtime!!! This matter needs to be resolved ASAP!!!!! My contact number is ********** 670.