Airtouch - Verizon is trying to collect a second time after buying accounts from Airtouch Ripoff Irvine California

I had an account with Airtouch Cellular in 1998. My phone bill became more than I could pay. I closed the account. It went to collection with Windham Professionals. I agreed to make two payments to this collector in August 1998. The payments were made and the debt was paid in full. Now six years later, Verizon has bought Airtouch and they are trying to collect on the same debt a second time. They have sent me to another collection agency called NCO Financial Systems. My credit report must look great by now. I just spent four months trying to close an account with AT&T wireless. I love my cell phone but these companies are really trying to take the consumer.
California

Michael
Sun City, California
U.S.A.