Called the NTTA today about a bill I received for ...

Called the NTTA today about a bill I received for dates after my car had been sold. They are holding me accountable because the party that purchased the vehicle failed to change the title - how exactly is their failure to follow the law and register the vehicle my responsibility? I have a signed and dated copy of the bill of sale which I will have to take somewhere to fax them because they don't accept email. Hopefully that will be good enough to end their nonsense. Forget that I'm actually a toll tag customer and have been for years; all that matters to them is how much they can stick to you. Ridiculous.