Damelin refusing to provide a copy of my Diploma

I studied at Damelin in 1999, I completed a DIPLOMA in Human Resource Management. I have the my results that clearly indicate that the Diploma will be issued in March 00. When I contacted Damelin to request a copy of the Diploma, I was advised that it is not a Diploma but a short course. I paid for the the HRM qualification but Damelin cannot give me a copy of the Diploma. I sent them a copy of my colleagues Diploma but they are adamant that it is not recognised as a Diploma. I have app**** for a job and this imperative that this issue is resolved.