NCO Financial Systems, Inc.
507 Prudential Road
Horsham, PA 19044
DV them. CMRRR letter. Don't call. Don't Email. $4.66 is a cheap, effective way to get rid of them when the debt is far, far past the CRA reporting period.
Nothing fancy.
"You called and contacted me about a debt you claim I owe. In accordance with FDCPA, send me validation of this debt."
Send 'em just name and address. Trust me, they can cross reference by many things to find the info in their computers.