INCORRECT BILLING FOR 4 MONTHS!!!

How many more times must I phone your pathetic call centre line and how many more *********** agents and team leaders must I speak too??? My reference no *** dated 15/06 refers.I upgraded on the 15/4/2015 to a smart chat 1G total monthly package payable R200. I van been charged R309 per month since April 2015. My circumstances changed due to my work and I approached Cell C to help me with a different type op contract....ref no *** dated 15/06.After a month numerous follow up calls from side with regard to my account and the migration department, I was finally migrated to a Top up 200 (or something like that!) and should be paying R210.00 per month. Today 4 months later my billing is still incorrect from April 2015 and I am still being charged for an open line. I have spoken to 5 of your agents from call centres in Jhb, Dbn and who knows where else as well as a team leader....and everyone is passing the buck and blaming another department....Can this please be sorted out now and my account fixed....that's if the accounts department to which this was transferred apparently 3 times already!!