Double Billed, No Apologies

I upgraded and cancelled an old one that had lapsed in November 2020 however I got billed for both accounts this month and the consultants in the upgrade/cancellation department are sending me from pillar to post. One said the cancellation was still pending and they are not sure why. Another said I got billed for both because the consultant who initially dealt with the upgrade made an error and I got charged both without the contract discount and that they would escalate and ensure I was credited. I've been on the phone for an hour and both times I was sent around to every department and eventually my call got cut. Please reimburse me or cancell all the contracts I have with vodacom. Thank you.