Telkom cancellation not done

I have cancelled my telkom landline and internet the 8th of 8th April 2021 as I was relocating in May. Got 2 case numbers, both was lodged, in progress, job done and resolved and was closed the 9th of April 2021. Just to receive sms now, 24 November 2021 saying that I owe them still for all months since May. After I have called them and gave everything they said that case was not clear. Now it must be investigated. I will never take out or refer anyone to Telkom again.