Robert's note above is absolutely correct in that you should not be trying to validate a debt with a CRA.  The only thing you really do with the CRAs themselves is dispute information found in your report.  They will in turn ask the reporting organization to verify the debt. 

Regarding the address...  the one that is used in Experian's online dispute system is not what you mention.  They list:

Experian
PO Box 9701
Allen, TX 75013 

Hope that helps!