Assistant sneaks out to go home without assisting

I booked in my Ipad mini for repairs on the 8th of January at MTN morningside, in which Tumi assisted me. 1 month later, there is no response, no sms or anything to let me know if my Ipad has been repaired or not. I tried phoning the store, they do not answer their phones. I phoned MTN Midrand to query if they have received any Ipad Mini using my EMEI number, they did not have any records of that. They gave me the Istore number for Midrand to find out, which I did and they also did not have any records all over Johannesburg and South Africa. One afternoon I was lucky to be answered by Siya at Morningside, whom I told the story and said she will write an email to Tumi telling her to respond as soon. To my surprise, Tumi did not respond, nor bothered to phone me back. I went to MTN on Sat 13 Jan to find out on wtas happening. I spoke to Tumi who seemed not concerned and told me that Siya never said I shuold respond to you, REALLY!!! She told me the repair centre was closed on a Sat. I asked for the manager, which she said she is going to get but dissappeared on us to go home without any feedback. She left us waiting like mad people. I want answers on where my device is Please.