Paying for non existing service and non existing data!

I initially started my relationship with Telkom back in 2017. Within the first 6 months I visited there store 7 times to dispute my Wifi connection ("No internet access") and data depleting each and every month on the 4th day of the month (120GB night and 120GB daytime). Each time I got there they couldn't find any logged disputes/queries and each time I was told to call a number or that they would call me back and then never to get back to me. After 7 months I changed my contract and upgraded to even more data in a month, still my data was disappearing. The tech team simply said all they can see is it was used from 00:00 to 00:00. Again many visits and queries and promises from there side - to date the issue remains unresolved. During September 2019 I requested Telkom to cancel my contract online and via email I was contacted on the 3rd of October 2019 via email saying they received my cancellation request. I again requested my contract to be cancelled during October, November, December, January and February. It is now April and I have been invoiced and debited each month since October. They simply stopped replying to my emails and queries again claiming non were logged. Hence I have to date paid for 6 months of data I cannot use and requested to be cancelled. This is unacceptable! Telkom is literally the WORST service I have ever encountered. I mean it even took them 7 months to figure out that I couldn't log into my account because they misspelled my name and incorrectly captured my cellphone number.