Unhappy customer

I upgraded to explore sometime last year took price lock, which was great at first until now recently my package was supposed to be R599 but I get charges that's more than our agreement... made several calls to enquire and when I spoke to one of the consultant who assured me that I was instant in credit. The following month I got a bill of the same amount called on their call center got a refs SD ********** but no response to wether my query was resolved or not, few days ago my service was disconnected saying I'm owing R1780 which I'm paid my normal amount we agreed on,. But upgrading I created problems for myself... I want my service to be reconnected or I'm taking this matter further. This is a get rich ****.