Being billed for a cancelled service

I have sent cancellation forms through since 18/09/2017 and each time got an email to say it will be processed. I eventually went into telkom in Greenstone and the one guy helped me to cancel my line and adsl Line..... Yet I am being billed for a line and a 4mb adsl Line when I only ever had a 2mb line. No matter who I talk to.... no one will log a dispute or Sort this account out.... I will not pay for a service I do not have.