No one knows where the repaired device is

The Boost tablet was sent for repairs on the 5th January 2016 as it kept rebooting itself (still under warranty), I was told to come and check it in 4 to 6 weeks. I went to the store on the 6th week but the device was not returned from repairs yet, the Lady who was assisting me tried to call CellC repairs but no one picked up, she then took my contact details and promised to copy me on the emails (I'm still waiting for that), I went back to the store on the 9th Feb Mohau tried to assist me but he couldn't trace the device, he successfully mailed Diviesh Juta who then responded and said we should contact someone else. Surely service employees should know with whom and how to escalate queries.<br> Mohau requested the EMEI numbers last month and now he's not responding to my emails, No one is giving me feedback, ALL I NEED IS THE DEVICE WHICH I PAID FOR.