TELKOM CALLS FOR FIBRE WHEN ALREADY A VERY ANNOYED TELKOM CLIENT

I have a fibre line with Telkom. They have been phoning me since about 6 weeks ago. Kept telling them that I have a line and am not interested in an upgrade. Eventually blocked them after a week as they phoned every day. I unblocked them again over the weekend as they are still phoning me. Got a call again at 11h28 today. Told the person I have an account and to take my name off the database. She advised that she could not. Asked her to transfer me to someone who could. She advised that she could not do that either. Why am I still being contacted if I am already a client of Telkom. I dont want to be rude to these people as they are only doing their job but enough is enough now. I get calls when I am busy and need to either kill the call or answer when I am trying to do something which is getting very irritating. Please help