The cra's need your SS# on the dispute letter. It is required when you order a report so why are you not wanting to put it on a letter directly to them?
Therefore in order to verify you are WHO you are they require this on a dispute too. It is for your protection.....and I have no problem giving it to them to prove who I am. But I would not give it out unless I know they need it to identify me. I just don't see the problem with sending a CRA your SS#. I can remember working in banking as a teller and asking for Drivers licenses. You wouldn't believe how many people would huff and puff about that! It was so I could identify them and for their protection. It wasn't like I wanted to be a pain in the butt!!!
Guys and gals I am talking about a credit card company not talking about experian, transunion and equaifax.