No help

My decide (Samsung Galaxy Tab 4) is only 6 months old. It has now been sent for repairs for the second time. I logged the call on 23/11/2015. The device was collected from me on 25/11/2015. One week later I called the call center to check the progress of the repair. ....according to the call center it was assigned to a technician on 23 November, but that is actually the date the call was logged. I contacted the courier service and they said the parcel reached its destination on 31 November. I phoned on 01, 02, 04 December but still there is no update. I phoned today (07/12/2015) and they can't pick up the reference number. When I logged the call I said I want a new device and not a repair because the device is only 6 months old and this is the 2nd time it has problems and according to the consumer act I can get a new device. I need this device for work, so I need a device that actually works and is not in for repairs all the time