Refuse to Honour Warranty Claim

My handset packed up while in the Warranty Period. This is a Company Contract with a iPhone 6 handset.<br> <br> I took it to Service Centre for repairs, they found that it must be replaced under the Warranty Claim. They issued me with a COL *** number to collect a new handset on the 19th Of June 2015. I phoned the Call Centre Numerous times to arrange delivery. They issue me with the following Reference Numbers NS ***2, KR ***7, JD ***4, AE ***8 and IC ***5. Every time when I spoke to an Operator and ask to speak to a Supervisor they just flatly ignored my request with some excuse.<br> <br> I am waiting now for more than a month for any professional assistance for MTN to honour my contract with them, what a disappointment !!!!