21 G data

I bought 21 G data on Saturday and I am supposed to receive 3G a day , I use the data for work purposes. This morning I woke up @ 7 am and the data is already depleted ,I called MTN to find out what happened first consultant was rude and hung up when I asked for the complaints e-mail address her name is Nyameka time 10:01. I called again spoke to Sthembiso @ 10:09 who advised that he can only pick up data depleted @ 09:45 which is the 1G I bought myself 5his morning in order to work. To make things worse I have been directed from customer care and network coverage team wasting my time trying to sort things out, still cannot work since I do not have data