emergancy airtime

What I normally do when I run out of data is that. I would take 10rand emergency airtime and transfer it into data. So tonight after taking the airtime it refused to transfer into data then I called into the call centre at about 00:50a.m. A guy called Sipho responded to the call and when I explained what is happening to him he said its because I had the exact 10rand amount on my account but when I tried telling him that this is what I normally do. He wanted to tell me otherwise. You can even check my data and airtime transactions. He needs more training and his attitude needs to change too