Charged for a unit that was returned!

Good day. I am extremely frustrated with you, Vodacom. I upgraded my Wifi last year. For some odd reason, my cellphone number was upgraded. After spending long hours on the phone trying to sort it out, it was. However, I am still being charged for the unit that was returned in January already.After I was promised that my cellphone contact would go back to what it was. I even received an sms to confirm that Vodacom received the unit. I am not prepared to spend hours on the phone again, let alone having to speak to multiple people. As a Vodacom customer since 1999, I ask you to fix this darrn error and refund my account! Thank you. Your frustrated customer