Online upgrade failure

Did a online upgrade and gets diverted telephonically to Mondo if I call 083 135....they keep on dropping the line in my ear and doesn't even call back.??Very unhappy as an loyal 13yr plus Mtn customer and why do Mondo handle online upgrades????Ive called 3xtimes already...gets diverted to Mondo dept and then phone line goes dead...its 15h57pm.