Telkom mobile staff useless

I bought wifi router which comes with 10gb per month from eskom online. Device was deliver on June 2019 only to find out that it was faulty. It was never used due to that. Contract was canceled and the device was collected on December 2019. To my surprise telkom still debit my account even though i communicated with them countless times. They gave me case number after case number but no help. When will you stop debiting my account. I'm really sick and tired of your unprofessionalism.