The place where I work was sent a payment notice (we don't have any TVs there). There was a strict instruction that failure to respond was a terribel thing and bad things would happen to us. There were lots of ways to respond if you wanted to pay or wanted to claim you already had a license.
There was no way to tell them you didn't need a license.
The next step is [they say in the letter] that they send an enforcement officer to your address.
If they just had a general phone number or a "we don't have a TV" phone number they'd have saved themselves at least the cost of sending someone out to try and hassle us ... and I'm sure a lot of other people.
It's not my job to chase up their failure to provide contact details on a demand for money.
OT: We got a parking fine when I took my wife in to have our baby last week. The number to call to pay the fine is the wrong number ... gah! I'm just not sure if this is malevolence.