Mtn data for unisa students

I am a unisa student who used her personal number to send through the text to get a study data. Indicated which number is new abd which one is my personal one that unisa has. To my surprise data was loaded on the old number abs not new number i bought. I want to correct this error and i am told to contact unisa. But they not working and the phones rings without an answer. Can mtn help and changing this decision because i do not want my old number to be contract after two months of free data or get surprises that i owe mtn. I called their 5 different consultants who are supposed so be champion's but aint helpful. I went to their store today at quagga centre still i was told the is nothing they can do because they cabt access corporates account i must lsy my query with unisa. But unisa is not helping and coming to the party. Please assist in correcting this error please