Where do I start?

I wish I could rate zero stars because one is being generous. I have been receiving final notices for payment on a TV license. The only problem is that that person is not me. They are sending all their communication to the wrong person. I have phoned them on 3 occasions to inform them that the number they have is incorrect as the number is my contract number and has been for years. Initially it came with promises that my number will be removed from their system but to no avail. Then I emailed them. Again, same promises, same result. This morning was the last straw. When I phone again, the phone was thrown down in my ear. It is a completely unprofessional and utterly incompetant company.