If you've disputed inquiries and they came back verified.....or not deleted, then yes, send a
non PP letter to the creditor or CA that pulled your CR.
Then the creditor will need to provide proof that they were authorized to pull your CR. If they can't, they must delete it.
One thing to keep in mind is if they have an acct (cc acct, collection acct, etc) on you, then that would be considered permissible purpose.