Nu Debt has no clue

If i could get zero starts, i would. This company has been harassing me for the past 6 to 8 months over the unpaid TV license of a person that i do not even know. I have sent numerous messages, informing them that they do not have the correct contact details for that person, tried to phone them, but after wasting more than 3 minutes of my own air time, there is still no consultant available. How does one get them to stop sending these messages. Blocking them does not help, after a few weeks the message pops up again under a different number. They are just so *********** and it appears as if their administration is in shambles. They are just annoying and irritating.