Not satisfactory

I did my diploma in HR management with College SA under optimi college after I was referred to them by a trusted friend. I am yet to get my diploma even though it's almost a year since I wrote my final exams. No communication whatsoever from the college in terms of how I will get my diploma. I keep calling them and being told someone will get back to me and no one ever does. All I want is a time frame of when I can recieve my diploma that I completed already. Very disappointing because my experience while studying was so good with the college so not sure what's happening now with them