Debit for a cancelled account

In January 2015, I cancelled a data contract with Vodacom's cancellations dept.I was still debited with a subscrption charge for Feb 2015, despite providing the 1 month cancellation notice as required. the contract is showing as terminated on Vodacom's system and no service is being provided. i ask therefore, why debit me if they are not going to provide a service. when i raised this under ref no. ***, i was told to take it with the legal department.