Dealing with the dreaded ANFI *facepalm*

I sent a request for debt validation, and they responded with a copy of a verizon bill.

I dont recall ever leaving a balance with verizon , the bill is dated 2006 though and I wouldnt even know how to go back and prove I paid..I dont even bank with the same people etc etc

Does this count as "debt validation" though?

*Also I just got a score watch alert today that is has been updated to reflect "disputed"

Next step?