R800 bill after i request ed for a call limit???

Please tell me why would I receive a R800 bill after I went to the store in Goldfields Mall and request that my data line should be blocked if the cap was reached??? I went in to the store and requested the limit where I was told by Palesa that it will block when my 2 GB is reached it did not? I would like to know what is going to happen now? As I assumed the my line will stop and was told by your consultants that it will I received a bill of R800. I suggest that you as show of good will remove the R800 account and change my number so that it will block or further steps will be taken, feel free to contact me.