MTN is still my data

I had about 890 data in the morning around pass 11 to 12 they where setting around 210 when I called the call centre the lady that was assisting me told me that my datas expired without even looking what happened to them when I asked her if she please check for me when did I buy them she said on the 4th of this month I asked her how can they expire if today its the 30th she told that the system hasn't updated I should call after 2 hours of which I did now they telling me that I was in the internet for a long time I should switch off my datas now n than my datas are always on why will they despair 2day from 890 to 102 that's a ******* they stilling from customers