Poor customer service

I recently purchased a mobile phone on contract, I have had it for about 1 month and a couple of days,in any case, the phone is now constantly freezing and 2 of the apps are not working, I then went to mtn who then advised me that the phone would have to be sent away for a warranty repair, if no fauly found, I will be charged R300,what I found completely shocking was that the young unhelpful lady advjsed me that the phone would take longer than usual to be sent back to me as it is a busy time of the year, she also advised that in a normal case it takes 3weeks, so when exactly was I going to get it back,next year, she also added that they do not offer any courtesy mobile phones, I would like rhis matter to be looked into,if the resolution is not satisfactory I will definetly be ending my contract and take my custom elsewhere where it would be valued