Well, you have three options:(posted 7613 days ago)1. Ignore the letter, the debt is probably time barred anyway !
2. Write back with a SARN, you find out what they are in the Do's & Don't section, and again dont worry, the debt is probably time barred.
3. Write/Speak to the police and make an official complaint !
Are you sure that you havent given out your address to anybody else, signed on, got a council tax bill or anything like that ?, thats wheere they could have picked up your name/address from.