I've had the same experience with EX. They seem to validate everything. Send the dispute by mail, you will need documentation to support your dispute.
Samer experience with EX as well.
After I mailed the supporting documentation 4 times, they deleted.
Prior to that - was coming back as "verified" when they other other CRAs had already deleted.
I thought it was the rule that if one CRA deleted then they all had to? I thought they shared the information? I'm sure I read that somewhere - may not be right though, just wondering.
How do they validate if the CA doesn't respond?
Edit; Just read my answer in another thread - apparently the CRAs don't do that with each other, but its up to you or the CA to inform them of the determination.
One CRA doesn't care what the other CRAs delete or don't delete. They don't communicate with each other.