Incorrect billing

I cancelled my landline on the 28 May 2018, to date I receive a bill every month. I have been calling Telkom to have this sorted out. This month I receive a bill again. Telkom is *****ing customers money, if I never received an email statement I wouldn't have realized they are debiting money from my account. I cannot be calling Telkom every month to have this sorted. It is time consuming.