New application and supporting documents lost

I went to MTN Mimosa Mall Branch to purchase a Sony Xperia Z3 Compact four weeks ago and spoke to Melinda. She told me she would call me when the phone was available in two weeks. On 6th Feb I went to check since I hadnt received a call from Melinda, only to discover the phone was there. Melinda then said she was too busy and asked her colleague Henry to help me. I signed all the papers with Henry and submitted my payslip, bank statements, ID and proof of address to him. He told me he would call me once I was approved. Later that same day, I got an sms from MTN that my contract was approved. By Wednesday 11 Feb when I received no call from Henry, I went to the store and was told Henry was off sick. I was told to wait for Melinda to return from her errand. She came back and refused to help saying I wasnt her client. Ennie then took over but she couldn't find my application form and supporting documents. Henry apparently took them home and I have to wait for him to return from sick leave before my contract can be activated! I demand my CONFIDENTIAL documents back and I am cancelling my application in favour of the competition. This bad service after being an MTN client for 13 years!