Account Closed But Billing Continues

Cell C must just make me understand why they wont stop debiting my account even after i have closed my account with them. On the 8th of May i called and asked for the account to be closed, i spoke to the lady by the name of Bridget and she confirmed that she has closed the account. This morning R278.00 was taken from my account, thats a lot of money for a closed account. Can I have my money back please since i have closed my account and payed all that is due to cell c!!!