CELL C NEED TO TAKE OWNERSHIP FOR INCONVENIENCE!!!

I took out an upgrade a year ago, I wasn't told that a limit had to be placed on data! A few months went by until I received an SMS stating the data is over an amount of R6000. I obviously couldn't afford that being deducted from my account! I received a call from cell c advising me of the same &that they would get back to me, no one got back to me. I waited &still no one got back to me, in which I refused to pay the monthly debit which included this data amount. I went in store&two of the staff couldn't assist me in which they advised me that I should call the customer care no. The customer line couldn't assist& are ***********. I received saying that I have been handed over, they also advised me to go in store as they wont be able to assist. I went in store& the manager advised me to call a number, after speaking to someone in the legal dep, they advised me that the manager of the store has to be held responsible&has to assist me as the phone was taken out in store&not telephonically. I went back in to the store&the manager couldn't assist me, so contacted someone from the head office to assist me. I am not willing to pay a bill of over 12 000 &cell c need to take responcibility!