Cellc Failed to debit my account for 3 lines of my 5 lines and now charges me an obsurd amount.

I took up a contract with cell c not too long ago for a Sony Xperia L3 and a Data sim that comes with 10gigs on a special for 129.00 a month for 24months when taking the offer the Sales agent had taken my banking details and advised I will pro rata for the month then get billed normal for the following month . I went for a business trip to Trinidad for a month and a half and come back home to south Africa to find my lines are blocked . Upon phoning the customer care center I spoke to an agent who is helpful and told me I owe 2108.44 Rands for the service - So I advised the agent that my accounts have been debited on time and only when I took the new contracts then the accounts was not debited at all leading my accounts to be suspended , I then advised the agent why would cellc debit 2 off my accounts and not the other 3 I advised the agent that I have data Sim on the number +*** that I receive 40 gigs on and that number was always debited on time and not its not debited at all . The customer service then advised me to confirm the first 3 digits of my account number and last 3 which has been confirmed correct over the recorded phone line. I advised the agent that the details are correct so why would cell c debit me for 2 contracts and not my other 3 , I then advised the customer service agent at the end of the day its not the customers fault and its the company CELLC that is at fault and should take full liable of the charges of the charges and have it waivered as per the fault coming from the company it self , All I want is my 3 lines active and cellc to admit to their mistake because when I was sold the 2 new contracts I gave the correct account details and If the sales rep that sold me the product entered the details incorrectly on system should be dealt with accordingly - please contact me on *** to help me resolve this issue because for this one the customer is right...