TELKOM - Still Billing a Cancelled Account

I ported my residential landline number from Telkom to Metrofibre on the 15th of November 2019. I spoke to both the Sales and the Service departments of Telkom in December to confirm that my Telkom account was cancelled and that I would not be billed any further. Needless to say I was debited on the 31st of December 2019 for R671.54 - I refuse to have to waste my time calling their call centre yet again!