Verizon wireless and debt validation. Should I call them? Negotiate?

I sent a dept Validation letter to verizon, today I received some letter that said to call them, they sent me nothing to validate this dept ( we beleive this acct was merged with our sons JR, SR ) I will not call them do I send the second dept valid. letter demanding they verify, and qoute all the laws ? (certified of course) the CRA said this was verified. please addvise me on my next step, this is the last baddy on the report it just keeps coming up its org date is 1999, I have read verizon is the worst one to get off and if it is mine I will over a pay to delete, if it comes to that thanks for all your help. I realize its probly not really affecting our score but if you go FHA for a home loan then every thing on your credit reports have to show paid.
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I would call verizon wireless for sure. Yes call them.
Also use the second letter for debt validation to make sure your rights are protected.
cell phone home phone verizon, bellsout all have to validate debt in writing or cease efforts.