Paying for contract that was cancelled

Dear Vodacom Customer Service,

I am writing to request urgent assistance regarding a contract cancellation that occurred in December of last year. My husband canceled his contract at that time, and we paid the necessary fees for an early exit as required. This payment was made and we sent the confirmation to ***.

Despite this, we continue to be billed for a contract that we cancelled. We have made several phone calls to your customer service team, and while we have been assured that the issue would be resolved, no action has been taken on our account to rectify this situation.