Contract cancelled but vodacom still debiting my account

I bought a contract from Vodacom online, but when i receive the device it was not what i was looking for. They came to pick it up because i was cancelling the contract with them. The courier company fetched the device from me on the 16 July 2019... end of July debited my account even though the contract was cancelled, then again now in August debited my account x2.

I am very angry with Vodacom because i dont understand why am i paying for something i do not have.