No service from MTN

People should not do bussiness with MTN they just take your money and dont give you any services especialy with there specials Example I am i student i bought R100's airtime to buy there 5GB any time and 5GB nightime data it was there back to school special and i keep getting an error saying something went wrong please try again later when i went into n MTN shop all advice they could give me is to keep trying , i have a contract with them where i get 4GB day and night data and some months i get loaded with not even the full amount of data i get loaded with like 3.5GB if im lucky