My experience with Ex is that they not only want your SSN, but also a copy of a current utility bill and copy of your Driver's license or they will send a letter back saying that they could not identify you with the submitted info and ignore your request.
Disputing inquiries is one area I have had no luck with at all. I sent 4 letters out certified mail, included SS#, all that stuff, and so far I've gotten two rejections. So I hope you have better luck.
If you don't get them removed--don't worry. They hardly count for anything.