FNB SMART DEVICE - PHONE FAULTY

I purchased 2 phones (Sony M5 Dual Sim) through FNB Smart Device in Dec 2015.in Jan 2016,both phones started switching off, they do not come back on with the power button.We have to physically plug the charger in & switch the phone on.This happens up to 10 times PER DAY.I called the Smart Device call centre on the 14 Jan to complain,they advised us to do a hard reset which we did but the problem persists. These phones are unreliable.I contacted the call centre again today to be told that my options were that I could either repair the phone (which I refused), cancel the contract or get a different phone for the same price.This was told to me by two consultants (1 in the technical division & 1 in the Smart Phone division). I called the call centre back to enquire what phones I could get for the same price only to be told that this was not an option!The consultant said that I could either cancel the contract or repair the phone. I said to her that I would like to cancel the contract. She put me on hold and then said that she has escalated the issue to her manager to see IF the contract could be cancelled.THIS IS RIDICULOUS! I want the contract to be cancelled immediately!