Data Houdini

Is there any other Cell C data contract customers experiencing issues with data running out too quickly? I am a lot on the internet, I know, but I do not download large files like movies unless after midnight. I have had 10gb run out the first four or five days of this month, I have topped up with 12gb, and now about another 4 days another 10gb of the 12gb is done. And recharging/topping up pushes my bill sky high.