Failure to do SIM-swop

I was due for an upgrade on 13 April 2015 and went to Autopage in Centurion. I received my new Samsung and a SIM but it has been 1 month today and still my new Samsung does not work. During this time I visited the shop several times and spoke to various consultants, I also received 2 extra SIM-cards but still no working phone. No response or update of any kind has been received from them and it is becoming a great problem for me to have a physical phone but not be able to use it. Not the 'old' or 'new' phone is working. I am at a stage where I want to take back the phone and cancel the contract at Autopage.