Nudebt threaten clients

I have been trying to cancel the wifi contract with Telkom for more than one year now as I HAVE NO WIFI. When inquiring from them about the wifi not working they will reply that it is the line and that I must pay outstanding amount after which they will repair. After months of paying for the service that I did not get, I stopped and now Nudebt is making threats on behalf of Telkom. Several attempt to talk to a human being at Nudebt failed as I can only log on their site and no reply or acknowledgement but threatening correspondence.