Being charged for phone in warranty

A week ago i took my phone in to get a software update done as the phone was not boot into the OS. I was told that should there be any damages to the phone by myself i would get charged courier charges and thats fine. The phone was booked in and after trying to call the repair call centre, no one was picking up all morning. I decided to go to gatemax MTN to find out the status of the repair only to be told that there is physical damages to the phone and the screen has some damages as well so the phone WILL NOT get repaired and i will be charged R350 for quotation. Should i accept quotation to get the phone repaired, i must pay a further R1600. Which is ridiculous as all the phone needs is a software update and I can assure there are no damages to the screen as said. I couldve done a software update myself but the phone is under warranty so Nokia shouldve dealt with this repair. I either want my phone back as is or an explanation as to why i did not recieve a call as yet explaining this to me. I will not be paying for a software update whilst my phone is under warranty! Once again another ******* my MTN. Once this contract is done i definately shall be moving to another operator.