Verizon Wireless - Allied Interstate ripoff dishonest fraudulent billing Oceanside New York

1...I have settled the debt with NCO financial system in Jun 17th 2002 with three people named "A Simpson , J.Linderoth and Ryan Nee" working for NCO financial system representing Verizon Wireless. Detail is just like the following.

The Man named "A Simpson" suggested that if I pay $176.17 right now in Jun 17th 2002, $293.62 debt will be settled. And so i have payed. after that, I called NCO financial system 2 times to make sure no debt. J. Linderoth and Ryan Nee confirmed no debt with Verizon Wireless.

2...And so I thought no more debt with Verizon Wireless. But most recent April 1st, 2004 I received notice from Allied Interstate.

3... But that notice letter has no name of worker dealing my debt case. When i replied to their letter, they did not send any proof that they are a legal Verizon Wireless collection agency but only threat. Even more, they changed the consumer department address everytime, firsttime Oceanside NY, secondtime PO Box 2455 Chandler AZ 85244-2455 , third address PO Box 361445 Columbus,OH 43236. Even they are changing phone numbers 1-800-597-1701,1-516-561-6497 , 1-866-221-3231 , 1-800-204-6521.

I don't know that, do i have to pay to them?
They (no name, only address) are still threaten me constantly.

Tae
lancaster, California
U.S.A.