FAULTY PHONE NOT REPLACED (NEW)

I upgraded my phone on 02/02/2015 (Samsung S5 Mini). It was faulty as it didn't want to recognise the sim card/network. Took phone back to store on 04/02/2015, but was told that phone needs to be sent to JHB for technicians to assess if phone is faulty. This was not communicated to me when I done the upgrade. Was told that I can only get a new phone once technicians assessed phone and declared it faulty. Was told in store when I done the upgrade that if phone is faulty within 7 days, I must bring it back and will get new phone right away! Staff at shop denied this on 04/02/2015. Sent phone in on 05/02/2015 and phoned head office on 06/02/2015, where I was told that this process takes 3 - 5 working days. Would mean I didn't have phone for 2 weeks... Then phoned store to say I am cancelling contract because I wasn't informed off all this. Customer Services Manager then demanded I pay contract up for full 24 months then I can have my contract cancelled! The salesperson didn't even give me a copy of the upgrade contract... This level of service is TOTALLY PATHETIC!!!