Unauthorized debiting in my accounts over terminated contracts

I have contracts with Telkom For a Phone a Tablet and Wifi of which all of the contracts were ending in June 2020 in April i went to them to notify them that i will not be upgrading my contracts except the one for the WiFi came June they send me an sms saying they have received my notifications of not upgrading , They debited which i reversed August they debited not even on the day they normally debit before i was even paid on the 20th August and they debited even double the amount and i have the sms and emails they send me saying they have terminated the contracts but still they debit