cancel still charging - no reply to my emails

after i cancelled my adsl line on 28 June 2018 i am still being charged for the subscription on this line i refuse to pay this account and if this is going to effect my credit rating i will take further action. after phoning twice and promises made by telkom to send me emails and sms to confirm i am disputing this account no one has gotten back to me.................................... i need answers please!!!!!!!!!!!!!!!!!!!!!!