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The problem is you have an open dispute with the account so they can't do anything until that dispute is over. Don't open a new dispute. Wait til the old dispute closes, and fax them a copy of that letter. i know, I've been there. This is one of biggest reasons not to dispute through the CRA"s because once you do that, they can't do anything to fix it, nor can the reporting party. It's stuck.
Check your PM's.