FNB devices faulty

I app**** and got delivery last year October for a Dell device from FNB which was faulty ie could not connect to the Internet which is all I needed it for. I took it to the FNB dot store in Eastgate and they confirmed it was faulty, after a lot of struggle with the call centre, got it picked up for evaluation, within the swap out period, so I asked for a new device. At this point I had no use of said device, paying out of my FNB account every month for the service. Finally FNB agreed to do a swap out and I got delivery of a 'new' device just before I was to leave Johannesburg, I work as a touring songwriter. I once again tried to get the device working and it did not so I went to the FNB dot store in and they confirmed that it was faulty, the same fault As the other device. As it was December could not tackle it before but decided to deal with it on my return. When I returned FNB stated they could not replace the tablet with a new one as I had missed the swap out period, I understand and take responsibility for the contract signed but am not prepared to pay 60% cancel fee for a device never used. Digital Planet Nomsa confirmed it was a fault I did not cause. Please help.